Baghdad, in 2004, three soldiers of an Army bomb-disposal unit are investigating a report of an improvised explosive device (IED). They use a sophisticated robot drone to examine the device, which consists of several undetonated artillery shells wired together and hidden under plastic/fabric sheets. The unit, led by Sgt. Thompson, decides that they can detonate the IED using plastic explosives that they'll activate from a safe distance. Thompson also says that the explosion won't cause very much property damage and should result in no loss of life.
A small cart is affixed to the back of the robot, which is then sent back into the blast zone. Before it can reach the IED, the trailer loses a wheel. Thompson dresses in a bulky bomb suit and walks down to the trailer. He picks it up and carries it to the IED, rigging it properly. As he walks back, his partners, Sgt. Sanborn and Specialist Eldridge, scan the immediate area for anyone they consider suspicious or who may be in the blast zone. When Thompson is about 25 meters from the bomb, but still in the kill zone, Eldridge notices a man running a butcher shop who is using a cellular phone. Eldridge yells to Sanborn and the specialist begins to run toward the man, ordering him to drop his phone. Sanborn tells Eldridge to shoot the man, who presses a sequence of numbers on the phone. The bomb detonates with Thompson still in the kill zone. The overpressure from the bomb kills Thompson despite the bomb suit; a large splash of blood hits the inside of the clear visor on his helmet.
Thompson's body is packed into a coffin for shipment home, Sanborn supervises the procedure. He looks over Thompson's possessions for a few moments before the coffin is sealed. Back at the base, Eldridge is sitting in the rec room when the base psychologist, Lt. Col. Cambridge walks in and asks Eldridge how he's feeling (in the wake of Thompson's death). Eldridge is still clearly upset over the incident; he dry fires his rifle several times, suggesting that if he'd shot the man with the cell phone, Thompson might still be alive.
A new leader for the team, Sgt. William James, arrives at the base. Sanborn meets him at his housing unit, where James is taking the plywood covers off his windows. When Sanborn suggests that James keep them on because of mortar shrapnel, James tells him that they won't be any good anyway if a mortar shell crashes in through the unit's roof.
The next day the team responds to a report of another IED on a narrow street in the city. After the initial investigation, where they link up with the Army platoon that reported the bomb, James is dressed up in a suit similar to the one Thompson wore previously. As James approaches the bomb site, he tosses a smoke grenade, which agitates Sanborn, who can't see James to instruct him further. James also is uncommunicative with his team members, another factor that Sanborn does not appreciate. James finds an artillery shell buried under a small pile of trash. He disarms it easily, and then notices a secondary wire leading away from it. He uncovers the cable and finds it connects to a junction of six more cables. When James pulls on the junction connector, six more shells are uncovered. Another cable leads to a nearby building. James disarms the six new shells; as he does, he notices a man quickly leaving the building, presumably the bomber. James flashes one of the small detonators from one of the shells and smiles at the man, who vanishes from sight. Back at their Humvee, Sanborn tells James that he needs to communicate more during operations and not treat his duty as if it's a solo act. James brushes his teammate off. James does the same later when he and Sanborn talk while grooming themselves for another day's work in the latrine.
The team is again called out for another bomb threat. This time, the bomb is in a car parked in front of a United Nations building. When the building is evacuated, James dons the bomb suit and walks toward the car, which suddenly becomes engulfed in flames. James uses a fire extinguisher to put out the fire and begins to examine the car while Eldridge and Sanborn take up their positions as lookouts. James opens the trunk and finds several of the same type of artillery shells he'd seen the day before. After a few moments, he takes his bomb suit off completely, knowing it won't protect him; there is enough explosive in the car to kill everyone nearby, including his teammates, even if they take cover. James disarms the shells and begins to search the car for the triggering device, a process that takes several minutes. At one point, when Sanborn tries to talk to him through a headset, James pulls it off and throws it aside. A few more very tense minutes pass as James searches the car. Sanborn and Eldridge notice several groups of Iraqis watching them from rooftops and from a minaret. They also see a man filming the incident with a video camera. At the car, James finally finds the triggering device and detaches it. When he returns to the Hummer, he lights a cigarette and is promptly hit in the face by Sanborn, who is again angry that James refused to acknowledge him or any questions he had. James appears strangely unoffended, nor is he angry at Sanborn. A colonel on the scene approaches James and is clearly impressed with James steady nerves and ability to handle such a crisis. When he asks James how many bombs he's disposed of, James gives him an exact number. The colonel is further impressed.
Back at the base perimeter, Sgt. James confronts an Iraqi kid who sells pirated DVDs to the soldiers. The boy, who kicks a soccer ball around and calls himself Beckham, had sold James a movie a few days before; James wants his $5 back because the DVD was poor in quality. When Beckham tries to hustle him further, James is amused and tells him he can keep the money if he's able to block a shot at the makeshift goal area Beckham has set up. Beckham blocks the shot and James agrees to buy another movie from him, mildly threatening him if it's defective.
The team goes out to the desert to detonate some of the explosives they've collected on missions. As they prepare to explode another bomb, James stops Sanborn to briefly drive down to the blast zone to get the gloves he left there. While he's gone, Sanborn tells Eldridge that, with the dangerous nature of the explosives they detonate in the desert, it would be easy to "frag" him by exploding the bomb while James is down there and claiming it was accidental. Sanborn seems pretty intent on doing so but Eldridge convinces him not to.
While heading back to the city, the team sees two SUVs parked on their route. They approach them and the occupants standing around as if they were any other threat. The men standing near the vehicles quickly obey Sanborn and his team, dropping their weapons. One of the men reveals himself to be a British commando and the bomb unit relaxes. The British man says they have a flat tire but have broken their jack handle. James offers them equipment from their Hummer. While one of the British men handles the flat tire, the Brit shows the bomb unit members the men he has captured (presumably high level Iraqi officials) to turn in for a reward. Suddenly, the man fixing the tire is hit by sniper fire and falls before the shot is actually heard. Everyone runs for cover; the British commando mercilessly shoots both of his prisoners as they run away; the reward for capture dead or alive is the same.
The bomb unit and the Brits find themselves pinned down. One of the Brits is killed while manning the Hummer's .50 caliber machine gun. The British team leader takes up a sniper's position on a small, rocky hill and begins to return fire with a Barrett rifle, shooting at a distant stone building where the enemy sniper and a small group are hiding. While adjusting the Barrett's bipod, the man is hit in the chest by the enemy sniper and killed. Sanborn takes up the man's rifle and James spots for him using a powerful scope. They fire several shots back at their enemy and run out of ammunition for the rifle. James has Eldridge search the dead man's pouches and he finds a full magazine. However, the man's blood has leaked onto the rounds and they must be cleaned off to cycle through the Barrett rifle. James helps a queasy Eldridge clean off the rounds. Sanborn is able to continue targeting the building and its occupants and, with James spotting, they're able to kill all the enemy troops. Eldridge notices someone who may be another sniper lurking at a position behind James and Sanborn and he opens fire. Eldridge is unsure of how well he did, but the other man is hit and killed.
The incident seems to form a stronger bond between James and his teammates. Having found that they can actually work well together as a team, they celebrate at James' housing unit, taking turns pounding each other in the chest and drinking. After discussing why James seems to be such a maverick teammate and how he got into their line of work, James shows them a box of parts he's collected from nearly every bomb he's disarmed. He says he keeps them as reminders of how dangerous his work is. Eldridge and Sanborn are a bit puzzled but now know, after the desert incident, that James is actually a team player.
On their next mission, Colonel Cambridge accompanies the team when they patrol a building where bomb making material has been seen. Cambridge stays outside while the team searches the building. Inside, they find the bomb making supplies and evidence that the bomb makers had just left. James finds the body of a young boy whom appears to be Beckham. He orders Sanborn and Eldridge out of the building spots a large incision in the boy's chest. He opens it and finds several pounds of plastic explosive in the body's abdominal cavity. He carries the boy outside to the Humvee. Outside, Cambridge is trying to clear the locals from the street when another IED goes off, killing him. In the immediate aftermath, Eldridge cannot accept Cambridge's death and wanders the area looking for him. He also finds Cambridge's helmet lying in the blast area.
Back at the base, James talks to a man who sells DVDs at the perimeter. James asks the man if he knows Beckham, however the man's English isn't very good and he tells him nothing. James asks the nearby sergeant if the man checks out & the sergeant tells him the man is cleared. Later, when the man packs up his merchandise and leaves, James jumps in his truck and forces him to take him to Beckham's house. James enters the house and finds another man in the kitchen who is scared but surprisingly hospitable. James demands to know where Beckham is at gunpoint, but the man doesn't know. James realizes he's mistakenly entered the wrong home and turns to leave when the man's wife appears and begins to yell and throw things at him. James makes his way back through the city to the base, passing hundreds of angry-looking locals. At the main gate, he announces he's a US soldier and is forcibly arrested. When the duty sergeant demands an explanation for his being off the base at night, James says he was at a whorehouse. The sergeant slyly asks him where it is.
The team responds to a call at night to check out a bomb blast zone. When they get there, they find that a bomb, possibly from a suicide bomber, went off near an oil tanker truck, causing a huge blast radius. James scouts the perimeter of the blast area and theorizes that the bomber didn't commit suicide but stood outside the perimeter and triggered the blast from there. James is furious and vows to find the bomber by ordering Sanborn and Eldridge to search the nearby streets. The three split up; shots are heard and Sanborn and James reconnect, however, they spot Eldridge being dragged off by two unidentified men. The two open fire, killing Eldridge's kidnappers but James hits Eldridge in the leg. James becomes severely upset at wounding his comrade and nearly breaks down in the shower, fully clothed.
The next day, James and Sanborn go to meet Eldridge at the helicopter that will evacuate him. As he approaches their Humvee, Beckham, unexpectedly alive, appears and tries to talk to him, but James ignores him. At the helicopter, Eldridge is bitter with James for shooting him, saying his femur has been shattered and recovery will take months. He also berates James for taking them into a danger zone to satisfy his adrenaline rush. Eldridge is flown off.
Sanborn and James respond to another bomb report and find a man standing alone in the middle of a large plaza. James has the translator order the man to his knees and he suits up and walks to him. When the man opens his coat, James sees he's wearing several pounds of C-4 attached to several steel bars which are locked together with large padlocks. The man pleads for his life, saying he has a family. With only two minutes left on the bomb's timer, James frantically tries to cut the locks, however there are too many and James must leave the man behind. Seconds later, the bomb goes off, killing the man and throwing James in his bomb suit out of the blast area. Sanborn rushes to him, thinking he's been killed like Thompson was. James is only stunned and wakes up. As they head back to the base, Sanborn, still shaken by the incident, tells James that he fears he will die in Iraq, having never had a wife or children. James tries to comfort him and convince his friend he'll make it back home and start a family.
The team's rotation ends and James goes back to his home and family. While shopping in a store, he is overwhelmed by the cereal aisle, which has too many products for him to comprehend. He also is unable to adjust to home life and his relationship with his wife and daughter becomes increasingly strained. James decides to return to Iraq and he does. The final scene of the movie shows him beginning a new rotation and approaching another bomb site in his suit.
During the early months of the post-invasion period in Iraq, Sergeant First Class William James becomes the new team leader of an Explosive Ordnance Disposal (EOD) unit with the U.S. Army's Bravo Company, replacing Staff Sergeant Thompson, who was killed by a remote-detonated improvised explosive device (IED) in Baghdad. He joins Sergeant J.T. Sanborn and Specialist Owen Eldridge, whose jobs are to communicate with their team leader via radio inside his bombsuit, and provide him with rifle cover while he examines an IED. James's insistence on approaching a suspected IED without first sending in a bomb disposal robot during their first mission together lead Sanborn and Eldridge to consider him "reckless". Back at Camp Victory, James befriends Beckham, a young Iraqi boy who works for a local merchant operating at the base, selling pirated DVD movies to the soldiers. The team is next called out to the United Nations building in Baghdad, where a parked car has a large bomb in the trunk. While James intensively studies the intricate bomb, Sanborn and Eldridge provide him with cover. Sanborn becomes increasingly concerned about three men watching them from a minaret and another filming them from a nearby rooftop. With the building evacuated, he suggests to James that the they pull out and let a team of engineers come disarm the bomb. James ignores and angers Sanborn by removing his radio headset and his bomb suit, and remains with the car until he disarms the device.
While returning from detonating bombs in the desert, the EOD team encounter a British private military company. They soon come under enemy attack, and three of the British mercenaries are killed in the ensuing firefight, which ends after Sanborn and James shoot the last of the insurgent snipers. For their next mission, the team heads to a warehouse to retrieve unexploded ordnance. While securing the warehouse, James discovers the dead body of a young boy who has been surgically implanted with an unexploded bomb. James is sure that it is Beckham, while Sanborn and Eldridge are not entirely certain. That night, James forces the merchant for whom Beckham worked to drive him to Beckham's house. Upon entering the house to which he is brought, James encounters an Iraqi professor and demands to know who was responsible for turning Beckham into a "body bomb". The professor thinks James is a CIA agent and calmly invites him to sit down as a guest of his household. A confused James is then forced out of the house by the man's wife, and sneaks back into Camp Victory with the help of a sympathetic guard. That same night, Eldridge is accidentally shot in the leg during a mission in which the EOD team successfully tracks down and kills two bomb makers. The next morning, James is approached by Beckham, who is alive and well. Much to Beckham's confusion, he is completely ignored by James. Eldridge blames James for his injury, claiming James unnecessarily put his life at risk just so that he could have an "adrenaline fix", referring to Sanborn's suggestion that the mission, which James had ordered, would be better suited for an infantry platoon.
With only two days left on their current tour, James and Sanborn are called in to assist in a situation where a man was forced to wander into a military checkpoint with a time-bomb strapped to his chest. James cannot remove the bomb nor disarm it in time, and is forced to flee before the bomb goes off. On the ride back to the base, Sanborn becomes emotional and confesses to James that he can no longer cope with the pressure of being in EOD, and relishes the prospect of finally leaving Iraq and starting a family. James is next seen back at home with his wife and child, visibly bored with civilian life. One night he has an internal monologue in the form of speaking aloud to his infant son, where he says that there is only "one thing" that he knows he loves. He is next seen back in Iraq, ready to serve another year as part of an EOD team with Delta Company.