Deep Impact opens to a starry night sky in Richmond, Virginia. The camera slowly pans down where stargazers and amateur astronomers are gathered with telescopes. Among these are students and faculty of the Lee High School Astronomy Club. Two students at this club are Leo Beiderman (Elijah Wood) and his girlfriend, Sarah Hotchner (Leelee Sobieski). As they look through their telescopes at the stars, Leo innocently asks Sarah about another male student who invited her to a student party.
Leo and Sarah's teacher, Mr. Perry (Mike O'Malley) comes up and quizzes them about some of the brighter stars. Leo correctly identifies the stars Mizar and Alcor, but cannot name a somewhat smaller, dimmer star a bit south of the other two, although he is sure that it is not the star Megrez, as Sarah claims. Mr. Perry, thinking it might be a satellite, suggests they take a photograph and send it to Dr. Wolf, a professional astronomer who sponsors the Lee High School Astronomy club. As Perry walks away, Leo and Sarah get into a brief, teasing argument about whether the unidentified star is Megrez.
Dr. Marcus Wolf (Charles Martin Smith, uncredited) arrives for work at the Adrian Peak observatory in Tuscon, Arizona. Seating himself at his work station, he finds the packet sent him by Leo, containing a photograph of the unknown star near Mizar and Alcor, and a cover letter asking him to identify it. Punching the stellar coordinates into his computer, he sees it is an uncharted object. His observatory's telescopes zooming in on it, he sees it is in fact a comet. Curious about it, he directs his computer to analyze the comet's position and calculate its trajectory. As the numbers begin to scroll through the screen, Dr. Wolf's curious expression fades into a look of severe worry and concern. An orbital interpolation graphic on his monitor overlays the comet's projected path on a small display of the solar system-- and a large dot quickly appears on the third elliptical line around the sun's icon; the comet is projected to strike Earth.
Seizing a floppy disk, Wolf saves all the data to it while instructing his computer to open a UNIX mail server to send the information out in email. After over a minute, however, he only gets two responses that the server is down. Exasperated and in a desperate hurry, Dr. Wolf grabs the floppy and stuffs it, along with the packet received from Leo, into a padded manila envelops. He writes his own surname and Leo's surname (Wolf-Beiderman) on the floppy drive and rushes out of the observatory to his jeep. As he races down the road, he struggles desperately to place a call on his cell phone to the Department of Planetary Sciences. Cell phone technology of the year (1998) being crude and limited, it takes him several long, harrowing minutes just to reach the automated answering system. Meanwhile, an 18-wheel big-rig truck is coming down the road. The driver, smoking a cigarette and listening to country music, is badly sleep-deprived; drinking a high-sugar soft drink to keep himself awake. As Dr. Wolf, pre-occupied with trying to finish placing his call and reaching a live person, focuses more on his phone than on the road, the driver's cigarette slips from his mouth, hitting his lap. The pain causes him to involuntarily look down while he bats at his lap and the ash from his cigarette. Both Dr. Wolf and the truck driver finally look up, alerted to the shine of each others' headlights, and see they're about to collide. Both desperately try to swerve, but the truck's cab lags behind in the swerve and Dr. Wolf's jeep slams into it, and he's knocked off of the road and down an incline. The envelope flies off of the seat beside Dr. Wolf and out the window of his jeep as it tumbles down the incline and explodes, killing him instantly.
Washington, D.C., one year later. MSNBC computers are transmitting a news report. In a conference room, a small team of news reporters led by Stuart Caley (Bruce Weitz) are discussing the resignation of U.S. Secretary of the Treasury, Alan Rittenhouse (James Cromwell). Rittenhouse is reportedly resigning because his wife is sick, although Caley's team doesn't buy it, going over a number of unpopular decisions recently made by Rittenhouse which has earned him more than enough enemies to force him out of his seat. The team jokes that with all the trouble Rittenhouse has recently gotten into, it's small wonder his wife is sick.
But reporter Jenny Lerner (Téa Leoni) demurs, saying Mrs. Rittenhouse is an alcoholic. She claims to have found out from a connection in the U.S. Treasury named Mike Woodward. As the news team starts discussing an idea on the price paid by wives of governmental figures, Jenny is asked about her connection to Woodward by Beth Stanley (Laura Innes), the news team's White House correspondent and Jenny's direct supervisor on the ladder. Jenny explains that Woodward has a crush on her, and she took advantage of it to get information on Alan Rittenhouse. At that point, Jenny quickly asks Beth about the possibility of stepping into a recently-vacated anchor position in their late-night weekend news broadcast, but Beth quickly rules Jenny out as a replacement anchor. As the conference adjourns, Jenny tries to press Beth on it, and Beth (a bit impatiently) explains why she feels Jenny needs more time to build herself up before being a weekend news anchor. She asks Jenny to find out more on the Rittenhouse resignation and have any updates on her desk by the next day.
Jenny meets her mother, Robin Lerner (Vanessa Redgrave) for drinks and lunch. Robin is preoccupied with the courtship of her now ex-husband, Jason (Maximilian Schell) to a younger woman named Chloe (Rya Kihlstedt)-- in fact, the age difference is such that Chloe is only two years older than Jenny, despite now legally being her stepmother. Jason and Chloe have very young twin children together and have just married that morning, and Robin prattles on about it.
Carrying on with her assignment, Jenny meets with Patricia Ruiz (Concetta Tomei), longtime former assistant and secretary for Rittenhouse. Ruiz is somewhat bitter because she was completely dismissed from her position without being conveyed to Rittenhouse's successor, because she followed him from his former position as Connecticut governor, not hired from within the federal pool. Ruiz confirms that Rittenhouse cheated on his wife, and she suspects he resigned because he was about to be found out. Ruiz, therefore, partially blames Rittenhouse for her now being out of a job. She says that Rittenhouse had had a special, secondary private telephone line installed in his office that only he was authorized to answer. But, Ruiz says, one day she overheard a name; a woman's first name she suspects as being one of Rittenhouse's lovers: Ellie. Ruiz also mentions she overheard Rittenhouse speaking about this Ellie in a conversation with the U.S. President himself.
Jenny arrives with an MSNBC news van to speak directly to Rittenhouse. They find him on a small boat with his young adolescent daughter, who is cold and suspicious of the news crew. Rittenhouse curtly tries to stick to his story about his wife being ill, until Jenny drops Ellie's name. Rittenhouse says he will only speak to Jenny if her cameraman turns his camera off. Once this is done, Jenny reveals what she's found out; more than enough to disprove the claimed reason behind Rittenhouse's resignation. Rittenhouse insists she knows far less than she thinks she does, and tries to appeal to Jenny's humanity, asking if she can understand that he wants to be with his family more.
Driving down the highway by herself now, Jenny speaks into her private voice recorder, making a personal log in which she hypothesizes that the President, not Rittenhouse, was having a love affair with this Ellie, and Rittenhouse took the rap for him to protect the President's own reputation and credibility, and was given significant financial compensation. Suddenly a black car hits hers from behind, not hard enough to overturn her car but hard enough to jostle her and make her take immediate notice. And this car is not alone-- three others are in formation, moving to surround Jenny's car. The car behind her bumps hers a second time. Scared out of her wits, Jenny realizes these men are intent on forcing her to take the nearest exit off the highway and shouts to the car on her left that she will comply.
The exit's re-merge into another highway is barricaded with a setup of road pylons. Jenny brings her car to a stop and the car in front of hers moves to block her from any further motion. The men in one of the cars pull open Jenny's driver-side door and identify themselves as FBI, ordering her out of her vehicle and into their own. One of them gets into Jenny's car to drive it where they are taking her.
The FBI agents bring Jenny into a kitchen (presumed to be the White House kitchen) where she is introduced to Morton Entrekin (O'Neal Compton), chief advisor to President Tom Beck (Morgan Freeman). When Jenny rebuffs Entrekin's mentioning that people knew about the Manhattan project (creation of the atom bomb) and kept it a secret, President Beck comes into the kitchen to speak personally to Jenny. Both Beck and Entrekin are clearly unenthused about Jenny's attitude, hinting that national security is at stake. When she drops Ellie's name, Beck asks her about it, although he pronounces it, "E.L.E."
Beck confirms that his administration has spent more money than can be hidden, and the federal budget is slated to be published in two weeks. They ask her to sit the story until then, appealing to her sense of what is in the nation's best interest. Jenny knocks both points out of the water quickly, at which point Beck and Entrekin decide to play hardball with her. Beck agrees to hold a press conference in two days, and offers Jenny a reserved second-row seat there, which he knows will be a major bump up from her current job. When she tries to press for more, Beck warns her sternly that she is already receiving a presidential favor-- something people like her can rarely even dream of-- and he can direct the Secret Service to imprison her indefinitely as a threat to national security. Jenny backs down quickly, politely asking for the first press question at the conference. Beck answers dismissively before ordering she be released.
Back at her desk in the MSNBC news offices, Jenny goes on the internet to research. Understanding now that 'Ellie' is an acronym for ELE, she enters that into a search engine. Dissatisfied with the results, she thinks and then enters E.L.E. with the periods. Puzzled at the result display of the University of Berkeley's paleontology department, she looks through the university's list of studies and notices a link to Extinction Studies. Reading through it, Jenny learns the grim truth: E.L.E stands for Extinction Level Event; the kind resulting from severe global-level catastrophe, such as the extinction of the dinosaurs... presumed to be the result of a massive comet or meteor strike on the Earth. Jenny is barely able to hide her monitor display when Beth stops by to invite her to dinner. Jenny politely declines as she is scheduled to meet her father and Chloe for drinks later.
The meeting with Jason and Chloe goes badly. Chloe gives Jenny a pair of pearl earrings as a present, looking to break the ice with her and try to establish a cordial relationship. But Jenny is every bit as bitter as Robin, about Jason's leaving Robin for a younger, more beautiful woman... and Jenny proves to be more vocal about it as well. E.L.E weighs very heavily on Jenny's mind as well, though she doesn't bring it up, further baffling Jason and Chloe at Jenny's coldness.
The day of the press conference arrives. Beth is attending, as MSNBC's White House correspondent, and is surprised to find Jenny there-- even more so when Entrekin (with whom Beth is acquainted) comes to escort Jenny to her reserved seat. Entrekin tells Jenny she will get the first question.
President Beck takes the podium to make the announcement of the comet. The comet was discovered one year ago by two astronomers, Marcus Wolf and Leo Beiderman. This comet is nearly as large as all of Manhattan Island-- large enough to endanger all of human existence. Beck downplays the comet somewhat, saying there is a "chance" of impact one year from then. He then reveals the whole Treasury fiasco was due to a secret joint project that the U.S. government had been undertaking with Russia for the past eight months. In orbit above the earth, a massive spacecraft is near completion, named the Messiah. This spacecraft is tasked with intercepting the comet and using nuclear warheads to try and shunt its orbit to avoid direct contact with Earth.
Beck calls up a video conference to introduce the crew of the Messiah-- mission Commander Oren Monash (Ron Eldard), spacecraft pilot Andrea Baker (Mary McCormack), medical officer Gus Partenza (Jon Favreau), navigator Mark Simon (Blair Underwood), Russian nuclear physicist Col. Mikhail Tulchinsky (Aleksandr Baluev) who is serving as Messiah's engineer, and a NASA veteran, Captain Spurgeon 'Fish' Tanner (Robert Duvall), who will land the spacecraft on the comet's surface so the warheads can be planted.
Beck gives the nation a stern warning that he is freezing all wages and prices, and will fiercely combat all attempts at material hoarding and profiteering. Work and paying of bills will continue as normal with as few disruptions to the world's way of life as possible.
Opening up the floor for questions, Beck calls on Jenny for the first question as he agreed to do. Jenny's MSNBC crew, in a frenzy over preparing their coverage of the conference, are stunned to see her at the conference. Jenny presses her privilege, asking three questions before finally sitting. Her third question shows everyone that she was on to the whole story before anyone else: she directly questions Beck on Rittenhouse's resignation, asking whether the true reasons for his stepping down was because he believed that the comet could not be stopped, and he wanted to spend time with his family because he believes they didn't have much time left to live.
Beck defensively answers that Rittenhouse served the country with devotion and resigned for personal reasons after a distinguished career. As far as Rittenhouse's concerns regarding the comet, Beck points out that over the next year, everyone on Earth will eventually have to come face to face with their worst fears. As much as he'd been downplaying it in the conference, Beck finally acknowledges that all of human survival is at stake. But, he insists, life will go on, and he is determined that humanity prevail even over this potential catastrophe.
When questioned by another reporter about the comet being named Wolf-Beiderman, Beck begins to explain that the two astronomers were killed in Arizona a year ago while racing to alert the government about the comet. As Beck explains this story, the Beiderman family is at home watching the conference, shocked at what they are hearing-- Leo is very much alive and well, at home watching with his family. The door rings and Leo finds Sarah there with her parents, and the whole neighborhood is beginning to converge on the Beiderman home, seeing that Leo is still quite with them all.
Newsweek publishes a story about Leo and the events regarding his supposed death. Leo speaks to his school and the students' families regarding his notifying Dr. Wolf about the comet, and he realizes that he was most likely presumed to have perished along with Wolf because Wolf shared credit with Leo about the comet's discovery. Leo quickly gains near celebrity status over having first discovered the comet.
The Messiah crew and their families are attending a small garden party which gives us a look into their day to day lives. Baker and Commander Monash are both married; Baker and her husband have a young daughter while Monash's wife is pregnant with their first child. Simon is engaged and looking forward to his wedding, but less than enthused about his fiancée's affinity for attending church. Capt. Tanner is widowed with twin sons grown to young adulthood and attending Naval Academy where Tanner himself graduated from. Tanner is also friends with Otis 'Mitch' Hefter (Kurtwood Smith), a senior NASA official who will serve as mission control director at a facility in Houston. Tanner and Hefter talk about the rest of the Messiah crew, about whom Tanner has concerns regarding their training being done in simulators, and they have little actual space flight experience.
Partenza talks with a young boy and explains the hazards of the mission: the comet's rotational period means the Messiah crew only has a seven hour window before the sun will 'rise' on the section they will be working on, and during the time that the sun is shining on that segment, there will be dangerous and volatile outgassings from the comet's interior. The Messiah crew needs to work quickly to avoid this hazard.
Later that evening, the crew members are relaxing and drinking at a bar, though Tanner sits separately from the others. He overhears them talking about him. The other crew members respect Tanner's reputation, but they downplay Tanner's having been the last astronaut to walk on the moon, and believe that he is only on the mission more as a public relations move by Washington, because he is a familiar face. Tanner finally goes over to their table and says he knows that the other crew members don't want him with them, but he insists they will need his experience-- all of their simulator training will be like a video game compared to the actual mission. He is the only one with actual experience landing a spacecraft on an actual landing surface.
Two months later, the Messiah crew is ferried by the space shuttle Atlantis to dock with the orbital station on which the Messiah was constructed. A news crew explains the Messiah's construction, and that it is powered by a prototype nuclear propulsion system code-named Orion, that was originally developed by Russian engineers for nuclear warfare. This propulsion system will allow the Messiah's crew to reach the comet well in advance of its arriving close to Earth.
Five months after the Messiah's departure, Caley's MSNBC news crew is meeting for another conference, discussing their ongoing coverage of the Messiah's mission. Everyone is asked about their role and latest contributions. Caley announces (to Beth's shock) that Jenny has been given a news anchor position for the coverage program. Being known as the one who broke the story on the comet, Jenny has likewise gained a great deal of national status.
The Messiah crew begins its approach to the comet, and they are in awe of its true size. They are making preparations to detach the main spacecraft from its propulsion system and fly down to the comet's surface to plant their nuclear warheads. Monash, Simon, Partenza, and Tulchinsky suit up for the planting of the warheads while Baker and Tanner are at the helm for the landing. Tanner gives an analogy of Mississippi River boat pilots, to explain that this part of the mission is in his hands and he will deliver the Messiah safely to the comet's surface. Baker smiles respectfully as she listens to Tanner's analogy.
Jenny begins her news program's coverage of the event. She tells everyone watching that interference from rock, gravel and gas from the comet will eventually cause them to lose video transmission with the Messiah. As she speaks, the picture is lost and Jenny assures everyone that the station coverage will continue and they will stay on air during the next hour in which the mission is being undertaken. The Beiderman and Hotchner families are shown watching the program together; Sarah's mother, Vicky Hotchner (Denise Crosby) is pregnant with her second child, and Leo and Sarah are growing closer.
As Baker and Tanner maneuver the Messiah for landing, they must fly through a veritable minefield of rocks caught in the comet's tail. Some of them are very large. Despite their best efforts, a few rocks hit the ship and some minor damage is sustained. They nonetheless manage to bring the Messiah safely down, fire tether pitons and land intact on the comet's surface. As they open the cargo bay doors so the surface crew can begin drilling into the comet to plant the warheads, Baker and Tanner start a computerized countdown. They have just under six and a half hours before 'sunrise' on their part of the comet.
Jenny begins an explanation of the next procedure of the Messiah mission: mechanical moles will be used to drill 100 meters into the comet, each one carrying a 5000 kiloton nuclear warhead. The Messiah is carrying eight of them in total.
Almost immediately the mission begins going awry. The moles prove to be unable to drill as deeply into the comet's surface, as quickly as is required. They are at just over an hour and a half before sunrise. Baker and Tanner, waiting anxiously in the spacecraft, know it is taking too long.
In the MSNBC news office, Jenny is interviewing a NASA scientist, who explains that soon as the sun rises on the portion of the comet that the Messiah is on, the surface temperature will rise 350 degrees in minutes, creating enough pressure to expel jets of superheated gas up through the surface. This will make the mission akin to working in a minefield.
On the comet surface, one of the moles gets stuck at 75 meters. The crew knows this is not deep enough; the warhead will just break pieces off the comet's surface. Commander Monash decides to descend into the shaft dug by the stuck mole to try and free it up, despite warnings from the other crew about the time pressure. Baker tells Tanner that in another six minutes, they won't be able to get back to the spacecraft for liftoff before sunrise.
Tanner orders the tethers be detached; he's taking the craft up to bring closer to the mole crew to pick them up; over Baker's desperate protests that such a maneuver may exhaust too much of the spacecraft landing module's fuel supply to get safely off the comet's surface. Tanner tells Baker to calculate exactly how much fuel will be needed to get off the surface; they will stop thrusters when they hit it. The mole crew is racing against time; one mole is at the proper depth but Oren is still struggling to reach the stuck one. The shaft went into a natural cave-like fissure in the comet's interior and the mole got stuck against the side. The mole crew works feverishly but unsuccessfully to free the mole. The landing module reaches the limit on spare fuel and Baker has to speak sharply before Tanner finally complies with her insistence to shut down the module's thrusters and land again.
The stuck mole finally begins drilling again and Commander Monash desperately climbs his tether cable so the crew can get back to the Messiah. The horizon is a mere minute away from sunrise and counting. Outgasses are beginning to explode up through the comet surface.
The horizon is bridged. Tulchinsky shouts urgently for the surface crew to lower their visors' solar shields. The crew is out of time and has to race back to the Messiah before they are caught in outgassing vents. Just as Monash clears the surface, a gas jet shoots him upward before he can lower his visor's shield. The full brilliance of the sun shines through his visor into his unprotected eyes. The rest of the crew reels him in by the tether cable and races desperately toward the Messiah landing module.
Mere feet from safety, an outgas jet erupts full force directly under Partenza, shooting him up off the comet's surface. Despite frantic attempts by both the mole crew, and Baker and Tanner, Partenza is blown out into open space and lost. The rest of the crew barely manages to reach the landing module; Tanner has to order Baker to lift off with the cargo doors open and close them as they go. Damage to the Messiah limits full video feed transmission back to Earth. Tanner relays the grim news that Tanner is lost and Monash is injured (his wife, Mariette, is seen crying as she hears the news).
Tulchinsky vehemently argues to go after Partenza. Tanner barely succeeds in persuading him that Partenza is lost, and all of them will die and the Messiah destroyed if they try to locate and retrieve him. That would doom the entire population of Earth.
Continuing news coverage at the MSNBC studio, Jenny gives a summary of Partenza's career in NASA in tribute to his sacrifice for the mission. Relaying updates as she gets them, she informs the people that Captain Tanner is now in command of the Messiah. It has docked with the Orion booster propulsion unit and is preparing to detonate the nuclear warheads. She cautions everyone that the blast effect will again nullify whatever video transmission the Messiah is able to send back to Earth.
Col. Tulchinsky coordinates the arming of the nuclear warheads. Tanner prepares to activate Orion boosters soon as the countdown is complete. Despite this, the Messiah is still caught in the nuclear shockwave and further damaged. All video and audio transmission is knocked out. President Back is seen in a White House office with Entrenkin, the cabinet, and a number of leading military Chiefs of Staff. A phone rings, and the member answering it looks at Beck grimly.
President Beck goes on the air to deliver the news to the country. The warhead detonation only succeeded in breaking off a significantly large chunk of the comet-- 1.5 miles wide-- large enough to cause catastrophic damage to the planet in its own right. Both this chunk and larger, six-mile main piece of the comet are still heading straight toward Earth. Houston Mission Control cannot communicate further with the Messiah although they are able to continue tracking it via radar. Its condition and the status of the crew are unknown.
Beck announces contingency plans that were in place from the moment of the comet's discovery. The United States and Russia will prepare their entire joint arsenals of Titan-Class nuclear missiles to launch into space as soon as the two comet chunks, now separately named Wolf (the larger, main body of the comet) and Beiderman (the smaller chunk broken loose by the warheads) are close enough for military computers to target them, in hopes that the comet pieces can still be shunted off their current course. The U.S. has also been excavating shelter caverns in the limestone cliffs of Missouri to use as a form of Noah's Ark. This shelter will be able to contain one million people, and enough animal and plant life to repopulate the Earth after all the dust settles. The shelter will contain all living essentials, food, water, and collections of human music, art, literature, and other physical creations of its culture, to rebuild the planet. 200,000 people have been pre-selected-- leaders, doctors, scientists, engineers, teachers, soldiers and artists-- for participation in the Ark. In one month, a national lottery of 800,000 additional people will be chosen. During these final preparations, Beck is declaring martial law. The US military will work in tandem with all state and city law enforcements. Extremely strict midnight curfews are going into effect, and minimal road travel will be permitted in the evening hours after local sunsets. Crimes against people and property will be dealt with far more harshly than is the usual national norm.
Other countries are preparing similar shelters in whatever manner they can. News networks all around the country are being faxed detailed instructions on how the lottery procedure will work. Showing his human side now, Beck closes his segment with a prayer for human survival.
Jenny's MSNBC news program goes back on the air to explain the lottery procedure. The lottery drawing will be on August 10th, picking 800,000 people by their social security numbers. The general lottery will exclude all men and women over the age of 50. Only the body of 200,000 pre-selected individuals, including people needed for the rebuilding of society due to expertise in particular fields of study, will have any persons over 50 years old. As Jenny speaks, her parents are shown watching the news broadcast; they know this means they will both be excluded from the lottery drawing.
Jenny's report continues to explain that civil defense teams are in place in all towns and cities with populations over 5,000, to organize and prepare underground shelters and instruct people on how to grow food and purify water and properly stock these shelters in whatever manner can be done. For the Noah's Ark shelter in Missouri, the 200,000 pre-selected individuals will be notified as her report is going on. After the lottery on August tenth, all unofficial travel will be blocked, all roads closed until the evacuation of all one million people by military personnel, to the Ark site, two days later.
As Jenny continues her report, the Beiderman and Hotchner families are watching together at the Beiderman home in Richmond. Their phone rings. Ellen Beiderman, Leo's mother, takes the call. The Beiderman family has been pre-selected. Sarah's father, Chuck, abruptly gets up, saying he needs to go back to the house in case his phone rings. However, it is clear that an instant rift has formed between the Hotchner and Beiderman families.
On board the Messiah, the crew is discussing their state. Repairs to the long-range communications will be hazardous due to hull damage in the areas of the spacecraft where they are located. There is limited life-support functions left. The Messiah will need to get close to Earth again to re-establish contact. The Orion propulsion module is still intact, but using it in order to get back to Earth sufficiently in advance of the comets will be risky because of damage to the spacecraft command module's radiation shields. As the crew ponders, Commander Monash, in sickbay with his eyes bandaged, says he feels they should try it. Tanner orders the Orion boosters engaged and the Messiah begins to race home.
Jenny is taking a walk through a park in Washington with her mother. It is just over one month before the comets are due to impact. Robin has reconciled herself to her impending fate. She's donated all of her antiques to the Ark, and takes comfort in her contribution to the preservation of human arts. Jenny, however, is guilty. She's been pre-selected because of her national status as a now well-respected news anchor, but she can do nothing for Robin. However, Robin says she's at peace with herself and is happy knowing that Jenny will live.
Leo goes to the Hotchner house, where Chuck is chaining up a motorbike he'd bought and is now quizzical over, knowing he will have no use for it. Vicky is on the porch watching a portable TV, where Jenny is delivering news coverage. As impact looms ever closer, society is teetering ever more precariously on the brink of total anarchy. A rental operator attempted to over-gouge prices on vital tools at absurdly outlandish rates, and was killed by an angry mob. Property and stores are being looted at increasing rates by both individuals and organized gangs. Many shop and store owners have completely abandoned these stores to the looters. Law enforcement attempts to curb and rein in this free-for-all looting and hoarding, are unable to keep up with the increasing volume. As Leo helps Chuck bar up and board up his home, he starts to ask Vicky about Sarah. Anticipating Leo's question, Vicky says that Sarah is up on a nearby hill by herself. Chuck has excused her from attending school any further.
Leo goes to Sarah with good news. He's talked to local civil defense liaisons, who have said that if Sarah marries Leo, she will be eligible for participation in the Ark evacuation. Sarah takes this news tentatively, saying she only wants to go if her parents can be included. Leo says his influence and fame come into play at this point; he's talked to appropriate liaisons, who have ensured that the whole Hotchner family will be able to be included in the Ark.
As days continue to pass, Jenny continues to report on how law enforcement and fire fighters have abandoned all attempts to rein in looting of businesses in order to finish preparing and stocking both the Ark and all local shelter units. Robin is seen applying makeup and donning a formal dress and jewelry, making herself stately and beautiful. Leo and Sarah are married by a civil justice as their parents look on. Vicky has delivered her baby; Sarah now has a baby sister. President Beck is seen at his desk in the Oval Office, deep in contemplation. Robin sits down in a comfortable armchair and lets her head tilt back, as if letting herself drift off to sleep.
The Messiah crew is asleep in their bunks, except for Commander Monash, who is still laying in the infirmary. He is stable, but permanently blind from his injury. Captain Tanner goes there to keep him company and talk. He explains his nickname of Fish-- his given name, Spurgeon, rhymes with sturgeon. The nickname was coined on his very first day at Naval Academy. As he and Monash bond, Tanner begins to read the novel Moby Dick to him, much to Monash's amusement.
August 12th arrives. All individuals and families selected both by pre-selection and the lottery are on street corners to be picked up by military buses to be transported to the Ark. The Beiderman and Hotchner families wait side by side with minimal belongings packed. As Leo shows his identification and marriage license to the bus official, everyone prepares to board. But to Leo's horror, the FCDA officials he talked to have left Chuck and Vicky Hotchner, and the baby, off of the boarding list. The official's orders from his superiors are not to admit anyone on the bus who isn't on the boarding list. He cannot let Chuck or Vicky on. Sarah, breaking into tears, refuses to leave her parents despite her father's attempts to push her on with Leo. The bus crew has no time to sit and argue, they force Leo, his parents and young sister on board the bus and take off. Even though she refused to leave without her parents, Sarah cannot help but run a short distance after it, crying to Leo.
Jenny is in the MSNBC offices when a phone call arrives for her. As soon as she is asked if she is the daughter of Robin Lerner, she, and everyone who overheard her repeat the question asked of her, all turn grim. Robin has died, and Jenny is being asked to positively identify the body and collect the jewelry Robin was wearing when she was found. Robin's cause of death is not stated but it is safely presumed she took her own life so her final moments and death would be peaceful and painless.
After identifying Robin's body and collecting the jewelry, Jenny sits on a street bench. It is nighttime, and rain pours heavily down from the sky. Jason, who had also been notified, happens to pull alongside Jenny in his car. Jason urges Jenny to get in and he'll drive her home; Jenny is wearing no protective rain clothing. Caring nothing about herself right now, Jenny laces into her father, taking out all her long pent-up frustration at Jason having left Robin in the first place, out on him. She gloats when Jason mentions that Chloe, frightened for her own life, has ran home to her mother, abandoning Jason. Jenny cruelly tells her father that she feels like an orphan before hailing a cab and riding off.
The Beiderman family arrives at the Ark cave. As everyone on the bus debarks and starts to be ushered into the cave facilities, Leo suddenly stops. His parents turn around and Leo grimly announces he is going back for Sarah. He is determined in this over his mother's frantic protests. Don pulls off his watch and rings so Leo will have something to trade. They tearfully hug him before he sets off in pursuit of Sarah.
Jason goes to see Jenny at the MSNBC offices. He tells her he's leaving Washington, but he has something for her; proof she isn't an orphan. He's brought several photographs taken at the family beach side house when Jenny was a child. Jason is holding her on his shoulders. Robin isn't in the photographs because she took the photos with her camera. It was a beautiful, happy day. Jenny seems nostalgic about the pictures but protests she was only 5 years old when the photos were taken, so she couldn't be expected to remember the day in question. Jason gives Jenny the photos to keep and says goodbye emotionally.
Leo has gotten himself a ride with a number of individuals in the loft of a private truck heading back to Virginia Beach. They are listening to a radio broadcast; the Titan missile strike has just been launched at the two comets, that are now 14 hours away from impact. Jenny goes on the air for a news report to cover the missile strike. The comet will interfere with visual tracking, so once again the country must sit and wait until military radar can see if the comets have been pushed sufficiently off course to miss direct impact.
Cut to President Beck at the Oval Office to deliver the results. For the first time, Beck is wearing only a pullover shirt and sweater; no dress shirt; tie, or suitcoat. The missiles have failed to deflect the comets off course. Earth has exhausted all options to prevent direct impact, and massive casualties are now inevitable. Beck delivers the dire statistics forecast for the impact:
Beiderman, the smaller fragment of the comet, will impact at 4:37 Eastern Daylight Time, striking in the Atlantic Ocean a short distance off of Cape Hatteras. A massive tsunami will be formed, racing toward the US Eastern Seaboard faster than the speed of sound. As it approaches the shallower waters off the coastline, it will slow somewhat, but wave height will build up to several thousand feet. All settlements on the east coast, including the cities of New York, Boston, Philadelphia, Savannah, Charleston, Charlotte, Washington, Atlanta and Miami, will be wiped out. Beck tells everyone in these cities that have any means of hurrying westward to leave immediately.
The main body of the comet, Wolf, will strike land in Western Canada several hours later. This will be a full Extinction Level Event. Within two days after impact, dust and debris will fill the sky and create an effect similar to a 'nuclear winter' that will make the skies dark for two years. Without sunlight reaching Earth's surface, all plant life will die, followed by all animal life.
But on board the Messiah, Captain Tanner has come up with one last option. He calls the crew together to explain his plan. They can do nothing about the Beiderman fragment, but he believes they can still stop the main Wolf comet and give Earth hope for survival. Outgassing has created a very large fissure vent in the comet's surface leading well into its interior. As the comet draws closer to Earth, the sun will melt ice and widen the hole further. The Messiah has four nuclear warheads remaining. If they can get these warheads into that Vent, the comet should be blown into fragments far too small to wreak the kind of catastrophic damage that the intact comet would cause. The crew has to get close enough to Earth to reach Houston Mission Control and get the manual arming codes for the remaining warheads, in order to synchronize the bomb timers properly.
Tulchinsky and Simon know that the Messiah is dangerously low on both life-support and remaining propellent fuel. It is not likely they can get into the cargo bay, or properly maneuver the Messiah for a second landing on the comet surface... much less get back off the surface once the warheads are planted.
Fish's silence and grim expression, however, show that none of these are factors in his plan. It is a suicide mission; the Messiah making a kamikaze run into the comet's interior and detonating the warheads. All of the crew will perish. The crew is grim at this reality, but all quickly accept their pending fate. The Messiah finally gets close enough to Earth to raise Houston Mission Control on audio. Fish briefly fills Hefter in and tells him to get the arming codes for the remaining nuclear warheads.
At the MSNBC news offices, final evacuations are underway. But there are seven people left in Caley's news team... and the last helicopter only has room for seven. As one of these must be the pilot, one of the news crew must be left behind for the helicopter to drop the others off on high ground in West Virginia before transporting Jenny to the Ark. Without any proper alternative means of deciding who must be left behind, straws are drawn. Beth draws the short stick, and quietly picks up her preschool-aged daughter, hoping for the best on the roads.
Leo has acquired a bicycle and arrives at the Hotchner house. The Hotchner family has evacuated, leaving their dog behind. Rushing to the garage, Leo manages to locate the key to unlock the motorbike. He takes it to search the highways to find Sarah. The panicked rush to get out of the city has brought traffic to a near standstill reaching for miles.
The news crew is rushing to board the helicopter. Jenny pauses to grab something from her desk. As she hurries to rejoin the remaining crew, they pass by the nursery. Beth is sitting there with her daughter Caitlin. Beth has realized the likelihood of successfully getting out of danger was very low with the frantic rush. She has resigned herself to her fate and gone to the nursery, hoping to spend her last few minutes holding and playing with Caitlin, despite assuring Caitlin that they will be safe. Despite the frantic shouts of the other crew, Jenny simply stares at Beth for a long minute. Suddenly she grabs Caitlin out of Beth's arms and rushes madly for the helicopter. Beth rushes in anguish after her.
But on the roof, Jenny thrusts Caitlin back into her mother's arms and announces that Beth is getting on the helicopter in Jenny's place. Nobody can dissuade her from this; she refuses to let Caitlin and Beth die. Everyone stares in amazement, knowing that Jenny is giving up her very life... but they have no time to debate the issue. Beth and Caitlin are ushered aboard the helicopter and it takes off, leaving Jenny behind. As she stands alone on the rooftop, Jenny gazes at what she took from her desk... it's the photos Jason gave her.
Racing down the highway, Leo continues his search for Sarah. It is she and her parents who spot him first, calling out to him and honking. Chuck decides this time there will be no further arguing. He half carries, half-drags Sarah over to the motorbike, physically picking her up and putting her on the seat behind Leo. He puts a motorcycle helmet on Sarah's head as Vicky works feverishly to attach a baby harness to Sarah's chest and slip the baby into it. Chuck tells Leo to hurry off and save himself, Sarah and the baby, getting to high ground. This time he and Vicky turn a deaf ear to Sarah's anguished cries of protest. As Leo races off, Vicky bursts into tears and Chuck hugs her.
Jenny, meanwhile, is shown pulling up to a beach side house... her family's house. She knows that Jason has gone here to spend his last moments before the tsunami strikes. She finds him on the beach, calmly staring out at the ocean. Saying that she lied to Jason about not remembering the day the photos were taken, Jenny finally makes peace and reconciles with her father. She hugs him and snuggles close, still frightened of her own impending death despite the decision she made to give her life up.
Time has run out. The Beiderman comet fragment breaks Earth's atmosphere and rushes for impact. Everyone for miles can see it race out past the coastline before it plunges deep into the Atlantic Ocean. A titanic mushroom cloud roars upward and outward from the point of impact. The skies turn dark; birds tossed helplessly about in the air as the tsunami begins to race inexorably toward the eastern coast. At the Lerner beach house, Jenny gives a brief sob of fear before Jason pulls her head against his chest and closes his eyes. The tsunami strikes the coastline and begins its run of devastation. We're treated to the obligatory scenario of New York City being destroyed. In the streets, hundreds of people abandon their cars, grab their things, and try to flee, but are very quickly overtaken by the tsunami. The final shot shows the city immersed underwater save for the very tops of the World Trade Center; the broken-off head of the Statue of Liberty, surrounded by cars and dead bodies, bouncing like a dropped basketball down Wall Street.
On the Virginia coast, people have abandoned their cars, racing pell-mell about in all directions, screaming frantically in a mad rush for higher ground. A few simply stand outside their cars and wait to perish. Among them are Chuck and Vicky Hotchner, holding and stroking each other for a final moment of comfort as the tsunami approaches. Leo and Sarah are part of a small crowd that have gotten off the road, racing for higher ground among the hills.
The Messiah has made final preparations for their interception of the Wolf Comet. The crew members have asked for their families to be brought to the Mission Control Center in Houston so they can say final goodbyes. Baker's husband and daughter, and Simon's fiancée are on standby. But Commander Monash's wife is still en route and hasn't arrived yet... and Fish's two sons were on active Naval duty and couldn't be reached. Accepting this, Fish gives a quiet prayer to his late wife, saying he's coming home to her at last.
Baker and Simon say their final goodbyes tearfully. Transmission is just about to be terminated when officers come rushing to the control room with Mariette Monash in tow. She reaches the control room in the nick of time, holding her baby son, who she's named Oren in her husband's honor. Commander Monash, although still blind, can hear Mariette and Oren Jr. He gives them an emotional farewell as Col. Tulchinsky sets the warhead timers and Baker and Fish calculate trajectory for the final interception run. They say farewell to each other; Baker closing her eyes and Simon closing his as Captain Tanner flies the Messiah through the vent into the comet's interior. The warheads detonate, shattering the Wolf comet into millions of tiny fragments. Leo, Sarah, and Sarah's baby sister are among a group of several dozen people that have gotten to the top of the highest hill they could find, barely escaping the tsunami. They watch as the shattered fragments create a firework-like light show in the sky.
Deep Impact closes with President Beck delivering an impassioned speech to a huge crowd in Washington D.C. sometime later, after the waters of the Atlantic Ocean have receded and settled back into the ocean basin. Acknowledging the incalculable losses of lives in America, South America, Europe and Africa, President Beck tells his people that they must remember those who died for them, and carry on with their rebuilding of the human way of life. The camera pans out for the final shot showing the U.S. Capitol building under reconstruction as the people gathered there cheer.