Television personality Pat Novak (Samuel L. Jackson) starts off an episode of his show "The Novak Element" by pointing out that every country in the world except for the United States is under high security with droids from multinational conglomerate OmniCorp.
His camera crew takes a look from Tehran where one OmniCorp employee, Rick Maddox (Jackie Earle Haley) is handing out red asset bracelets to one of Novak's reporters and camera crews as they observe the large droids and other robots doing a scan on citizens in the area. From inside a compound, a mother and her son, Navid (Noorin Gulamgaus), watch the droids do their work. Navid's father Arash (Meysam Motazedi) leads a group of suicide bombers outside to capture themselves getting killed live on international television. They launch their attack, with all the bombers getting themselves killed by the droids, though they succeed in taking out some of the EM-208 droids themselves. Navid runs out with a knife in hand. The ED-209 droid decides he is a threat, giving it probable cause to machine gun him. The camera crew captures all of this.
Novak continues by admiring how the droids handled the situation, pointing out that OmniCorp CEO Raymond Sellars (Michael Keaton) has the right idea to push forward for use of these droids in the U.S., but Senator Hubert Dreyfuss (Zach Grenier) is against it, having issued the Dreyfuss Act to prevent this type of law enforcement. Novak ends by asking why America is so robophobic.
In Detroit, we meet Detroit Police Department detective Alex Murphy (Joel Kinnaman) walking to a meeting with Chief Karen Dean (Marianne Jean-Baptiste). In her office are two other cops, John Lake (Daniel Kash) and Andre Daniels (KC Collins). Dean reprimands Murphy for the events of the previous night. Murphy and his partner Jack Lewis (Michael K. Williams) had gotten into a shootout with men working for crime boss Antoine Vallon (Patrick Garrow), killing six of them and critically wounding Lewis. Once Lake and Daniels leave the office, Murphy tells his story.
Murphy's story is told in flashback. He and Lewis have been undercover to crack down on a recent shipment of illegal firearms. Posing as buyers, they interview a dealer named Jerry White (Jordan Johnson-Hinds), but they begin to think he's selling dirty weapons. Acting like they believe Jerry is an undercover cop, they scare him into revealing that he works for Antoine Vallon. Murphy and Lewis run the serial numbers of the weapons being sold and discover something shocking: they are guns that should have been locked up in the evidence room, which means Vallon's got cops on his payroll.
On a rainy night, Murphy and Lewis go to a restaurant to meet with Vallon. Lewis insists that they need backup, since Vallon's guys might shoot them for target practice, but Murphy overrules his concerns, arguing that calling for backup will tip Vallon off. Inside the restaurant, Vallon and his right hand man hear Murphy and Lewis out, and appear to fall for their undercover identities. Unfortunately, somebody betrays Murphy and Lewis to Vallon and notifies Vallon by smartphone. Vallon immediately leaves the table.
While Vallon is standing up, a car pulls up in front of the restaurant and a group of gunmen armed with pistols and submachine guns open fire. Murphy and Lewis return fire with their pistols, pinned down in one of the booths. After a lengthy exchange of gunfire, during which several henchmen are killed, Murphy escapes outside by jumping through a glass window into an alleyway. A couple of henchmen are waiting in the alley to ambush him. Murphy uses a dumpster as a shield while advancing on and shooting at the henchmen. He kills two of them, and the remaining one escapes by foot. Lewis prepares to follow Murphy when a henchman hiding in the kitchen bursts out and fires on him. He manages to return fire and kill the henchman, but in the process is shot in his right shoulder. Murphy stays with him until an ambulance can arrive.
In the present, Chief Dean reminds Murphy that he isn't supposed to carry out such an assignment without talking to her first.
In Washington, DC, Sellars is at a subcomittee hearing with Senator Dreyfuss in regards to the matter of using OmniCorp droids as law enforcement. Dreyfuss argues that a machine could not feel anything if it were to kill anybody, even a child. On return to Detroit, Sellars meets up with his marketing associates, Liz Kline (Jennifer Ehle) and Tom Pope (Jay Baruchel). Realizing that more than half of the country's population will not stand behind a machine protecting its citizens, Sellars proposes that they get a man into a machine.
At the OmniCorp rehab center, Dr. Dennett Norton (Gary Oldman) and his assistant Jae Kim (Aimee Garcia) are tending to a man who has had his arms replaced with artificial robotic limbs. Although he is nervous to use them at first, Dr. Norton convinces him to give it a go. The man starts to play the guitar, and he and his wife are overcome with joy. The man's emotional levels begin to rise, which would interfere with the program. He tones it down but then says he needs emotions to play. Dr. Norton is then called away by Sellars. They, along with Kline and Pope, review potential amputee candidates for the man-in-a-machine program, all of them veteran police officers, but Dr. Norton and Sellars reject each one either due to their physical form or their personal reputations.
Meanwhile, it's revealed to us that the two officers Chief Dean shooed out of her office earlier, Lake and Daniels, are the men who betrayed Murphy to Vallon. They tell him that Murphy is going to visit Lewis at the hospital. While Murphy is inside the hospital, one of Vallon's men walks up to Murphy's car and plants a bomb in the left front wheel well.
Alex goes home to his wife Clara (Abbie Cornish) and 10-year-old son David (John Paul Ruttan). After putting David to bed, he and Clara start to get intimate when the car alarm goes off. Worrying that it'll wake David, Alex goes to turn it off. The car alarm is a trap, and it lures him outside, and the car is then blown up remotely. Clara runs outside to find her husband lying on the front steps of her house, burning.
Clara is met by Norton and his associates to discuss Alex's condition. He has suffered fourth degree burns, both his legs and one arm have been amputated, he is blind in one eye, and will probably be deaf. The team attempts to persuade Clara to give consent to use Alex for the program, but she is concerned as to what kind of life he will have.
Three Months Later:
Alex is at a party with Clara, along with Jack and his wife. Alex and Clara dance to a Frank Sinatra song. This turns out to be a memory that Norton and Kim are viewing as they put the finishing touches on Alex's new mechanical suit. They wake him up, and he is in shock as to what he sees. He grabs Norton by the throat and throws him down. Kim tries to shut Alex down as he runs out of the room, but Norton tells her to let him go. Alex continues to run until he hops over the wall of the facility and through a field. Norton tells Kim to shut him down.
Back in the lab, Norton speaks with Alex face-to-face and shows him just what is left of him - only his head, heart, lungs, and brain are there. Alex is horrified by this and requests that he die. Norton reminds him that Clara signed the consent forms, so if they let him die, the work will have been for nothing. Alex later talks to Clara through a video chat. She is happy to hear from him again. Afterwards, he later sees news reports on his attempted murder, a lack of evidence to trace back to Vallon, as well as interviews featuring Lake, Daniels, and Jack.
Alex is put through training and is set to get familiar with his program. As Maddox shows him, his suit can respond to a threat, taking out a firearm if needed. Alex is taken a simulator room where he is placed next to a basic robot. As shown on a monitor, the robot responds to threats quicker than Alex, who hesitates and is conscious of potentially harming civilians. Maddox quips that he "wouldn't buy that for a dollar".
In another training facility, Alex is put to the test against Maddox in an exoskeleton along with other robots. As Alex easily maneuvers through the robots' gunfire, he shoots them all. Norton tells Sellars that although Alex thinks he is the one carrying out these actions, he is merely carrying out orders as programmed. Kline points out that this is illegal, but Sellars thinks it's fully legal for a machine to think it is a man. Once Alex is done, he tases Maddox for good measure.
Norton drives Alex to his home where he will get to see Clara and David for the first time. David set up a "welcome home banner" for his father. Alex enters his home, and although both Clara and David are surprised by his new appearance, they still embrace him.
A public press conference is held to present the new and reformed Murphy to the city. While he is getting set up, Norton and Kim see on a monitor the emotions going through Murphy's head as they put the police database information into his head. When he starts to remember his attempted murder, he becomes overwhelmed and starts to have a seizure. Dr. Norton catches him and starts to get pressed by Kline and Pope to find a solution. He and Kim resolve to lower Murphy's emotional levels. He walks out to find Clara and David waiting for him. David says hello to his dad, but Murphy just continues walking with no expression. He passes Sellars and the mayor as they extend their hands to him. Once he steps out before everybody, the crowd goes silent. Through Murphy's vision, he assesses that nobody is a threat until he spots one man in the crowd, Thomas King (Dwayne McLean), who is wanted for murder. Murphy calls the man out to arrest him. King begins to run until Murphy hops into the crowd and shoots him with a taser round to the back, knocking him down..
Novak brings this up on the show as a reason for people to finally get behind this new program. He notes that King stood within spitting distance of two cops who could not identify him and that he has eluded the police for six years on charges of rape, assault, and murder, yet Alex was able to catch him within a minute. As a result, public opinion on the Dreyfuss Act begins to change. The citizens of Detroit begin to embrace Alex, giving him the nickname of RoboCop, though some are against this due to the belief that the police work belongs to human cops and not a robot. However, Sellars tells Dr. Norton to, for the meantime, keep Murphy away from his family.
At the police station, Murphy comes in as Chief Dean briefs the other officers on several murder suspects. Murphy says he will take on the case to look for a criminal named John Biggs (Robert Thomas). He patrols through the city on his motorcycle. He catches a few totally stoned junkies, getting one to tell him where Biggs's drug lab is. Murphy finds the lab and has a shoot out with Biggs's goons. Biggs tries to run but Murphy has him cornered. He tries to throw a grenade at Murphy, but he gets tased and drops it, blowing himself up in the process.
As Murphy is set to continue, he is stopped on the street by Clara. She pleads for him to hear her as she tells him that David is traumatized and is having nightmares. He rides off and accesses CCTV footage to show the reporters hounding Clara and David as she tries to take him to school. Unable to show his face, David retreats to the car.
Murphy rides back to his home and inspects the crime scene where is car blew up. He reviews the footage of the explosion to realize that David witnessed his burning body, leaving him fearful, anxious, and distressed. Afterwards, he locates Jerry White and pulls him out of his car to get him to give him a number to one of Vallon's goons. He traces it to locate Vallon's warehouse. When someone tips off Vallon to Murphy's impending arrival, he rallies his men to grab their guns and turn the lights off and watch out for Murphy with night-vision goggles. The crooks open fire on Murphy, getting his suit shot, but he kills all the men and finally shoots Vallon down. Murphy picks up a gun and scans it for fingerprints, picking up prints from Lake and Daniels.
Murphy returns to the police station, followed by Jack. He interrogates Lake and Daniels, showing the meeting through every monitor in the station to prove their involvement in the bombing. Daniels tries to shoot Murphy but gets shot in return. Lake admits that Dean was involved with both the shootout at the restaurant and the car bomb. He tases Lake and goes to confront Dean. Before he can get a confession out of her, Maddox, operating from the facility, shuts Murphy down. Maddox reports this to Sellars who is in his helicopter.
On another episode of "The Novak Element", Novak comments on how Murphy exposed the corruption within the police department, further suggesting why it's time to finally put the robots out on the street. Meanwhile, Sellars meets with Maddox, Kline, and Pope to talk about the state of Murphy's condition. Kline issues a statement to the public to say that Murphy is in critical condition. Sellars decides that they can use Murphy as a symbol of martyrdom to stir up sympathy. Additionally, the Dreyfuss Act is repealed. Clara demands to see her husband but is denied.
Sellars sends Maddox and other mercenaries out to destroy Murphy, preparing to tell Clara that Alex died from his injuries. Kline arrives at Clara's home and escorts her and David to HQ to meet with Sellars. With Kim's help, Dr. Norton runs into the facility where Murphy is being kept, warning him that the mercenaries are sent by Sellars and are there to kill both of them. Murphy wakes up in time to kill the two goons before they can fire at him and Norton.
Murphy rides his motorcycle to OmniCorp Headquarters and gets help from Lewis, who has rallied the SWAT team to assist. He tases one guard outside the building, forcing the others to stand down. He flips his motorcycle into the building, getting the attention of two ED-209 droids. They shoot at Murphy, but he gets them to shoot at each other. A third droid is caught in the chaos and falls from a great height, and Alex's arm is caught beneath it. As more droids come in, Murphy is forced to grab a submachine gun and shoot his left arm off. The droids shoot at him, bringing him down. Lewis runs in and stands in front of him, giving Alex a chance to run. He is found by Maddox and another goon, both of whom are wearing red asset bracelets, which keep Murphy from shooting either of them. Before Maddox can deliver the fatal shot, Lewis shoots him in the back and kills him, and then kills the other goon before getting shot himself. Murphy assesses the wound and determines it to be non-fatal to Lewis.
Murphy makes it to the rooftop of the building as Sellars is waiting for a helicopter. Clara and David are there with him, as are another mercenary, along with Kline and Pope. Alex orders the latter two to stand down, and they comply. He attempts to arrest Sellars for trying to have him killed, but he is also wearing a red asset bracelet, and therefore he cannot shoot him. Sellars aims his gun at Alex, and then at Clara and David. This gives Alex enough of a push to override his program and shoot Sellars, who returns fire. As Sellars dies, Clara and David rush to Alex's side.
A while later, Alex is given a new repaired suit. Clara and David are there to visit him. He smiles as they come in.
The last scene shows one more segment of "The Novak Element." The President has vetoed the repeal of the Dreyfuss Act once Norton testifies against OmniCorp's program. Despite this, Novak is still pro-robot, continuing to praise Sellars and bash Norton for being a whistleblower. As he concludes his show, Novak urges viewers to stop whining and to get with the program.