In 2154, two classes of people exist: the very wealthy, who live on a luxurious
space station called Elysium, and the poor, who live on an overpopulated, devastated Earth. While residents on Earth are policed by ruthless
androids, Elysian citizens live in comfort and safety, surrounded by robotic servants. They regularly use man-sized medical devices in their homes that keep them free from disease (so called
Med-Pods).
Max Da Costa (
Matt Damon), a former car thief and parolee, lives in the ruins of Los Angeles and works on the assembly line in one of the robotics factories of Armadyne Corp., the company that provides the space habitat, robots, and most of Elysium's weapons. Max grew up as an orphan and has spent much of his life in prison. After an altercation with a robot officer results in a broken arm, he reconnects with a childhood friend, Frey (
Alice Braga), who works as a nurse in the rundown County Hospital. Frey's daughter Matilda is dying of
leukemia.
When a caravan of illegal immigrants from Earth attempts to reach the space station, Elysian
Secretary of Defense Jessica Delacourt (
Jodie Foster) activates vicious mercenary Kruger (
Sharlto Copley), who works on Earth as a sleeper agent, and orders him to shoot down the shuttles in a covert mission. Disapproving of her methods, Elysian President Patel (
Faran Tahir) reprimands her, and Kruger is fired. Delacourt, vowing to protect Elysium and her own power, convinces Armadyne's billionaire CEO John Carlyle (
William Fichtner) to write a program that can override Elysium's central computer and make her President. In return, she offers to guarantee renewal of Armadyne's defense contracts for the next two hundred years. Carlyle agrees to the coup, and after creating the program in his office on Earth, he encrypts it and uploads it to his brain for safekeeping until his return to Elysium.
After an accident at the plant exposes Max to a lethal dose of
radiation, Carlyle has Max fired, and Max is sent home with a bottle of painkillers, having only five days to live. Knowing his only chance for survival is a Med-Pod, Max seeks help from notorious smuggler and hacker Spider (
Wagner Moura), who organizes the illegal caravans to Elysium. Spider agrees to get Max to Elysium, if in exchange, Max helps him steal valuable financial information from an Elysium citizen. Max agrees, after stipulating that Carlyle is to be the mark. Spider arranges for Max to receive weapons and several medical implants, including a fake Elysium ID needed to use the Med-Pods, a primitive
powered exoskeleton that increases his strength to rival the android sentinels, and a cerebral data uplink which will allow Max to transfer information from Carlyle's mind to his own. With help from a team including his friend Julio (
Diego Luna), Max intercepts Carlyle's spaceship, disables his bodyguards and steals his data (including the program), uploading it to his own brain. The team, however, finds the data scrambled by Carlyle's security measures and cannot transmit it to Spider.
Delacourt secretly deploys Kruger and his men to rescue Carlyle and recover the program. In the ensuing firefight, Carlyle is mortally wounded, Spider's men are gunned down and Julio sacrifices himself fighting Kruger so Max can escape. Max is stabbed before getting away, and seeks Frey for help treating his wound. She asks him to help smuggle Matilda into Elysium so she can be cured of her leukemia, but he refuses, believing it to be a suicide mission. Meanwhile, Delacourt locks down Los Angeles airspace and sends Kruger's team on a manhunt demanding Max be captured with his brain undamaged, as it now holds the only viable copy of the program. Max returns to Spider to extract the information from his head, and they discover Carlyle's program. They realize that during the reboot it performs, they could change any data they wanted, including making all of Earth's residents legal citizens of Elysium. However, the lockdown prevents Spider from launching a ship for Max until his men can crack the jamming signal, by which time Max will be dead.
Max instead bargains with Kruger to be taken to Elysium in exchange for the program (threatening suicide by a live grenade next to his head). Kruger, who unbeknownst to Max has captured Frey and Matilda as hostages, agrees. With the lockdown lifted so Kruger's ship can leave Earth, Spider hastily gathers a team and also heads for Elysium. As Kruger's ship is approaching the station, his men attempt to disarm Max of the grenade, and it ultimately detonates, severely mutilating Kruger's face and disabling the shuttle which crash-lands into Elysium. Delacourt seizes the opportunity to declare a state of emergency and relieves President Patel of his duties.
Max, Frey and Matilda are captured from the wreckage and handed over to Delacourt. Carlyle's security measures for the program are discovered, and it becomes clear that extracting the program from Max' mind will kill him. Delacourt is unfazed by this and orders her men to proceed. Meanwhile, Kruger's men put their badly-disfigured boss in a Med-Pod in the armory nearby, and his face is reconstructed. The team is chastised by Delacourt for letting the situation get out of hand, but the mentally-unhinged Kruger now has his own plan; he wants the program for himself, to become President and make Elysium his private playground. He stabs Delacourt in the neck and leaves her with Frey and a comatose Matilda. Despite Frey's best efforts, Delacourt refuses her help and dies. Max escapes from the data extraction team, and rescues Frey and Matilda, sending them to the surface of Elysium to find a Med-Pod.
Realizing that the Med-Pod will not work on the now-comatose Matilda as she is not a citizen of Elysium, and also knowing that between his radiation sickness and the program in his brain, he is a dead man walking, Max resolves to use Carlyle's program to make everyone a citizen. He meets with Spider and his men, who landed safely on Elysium during the chaos, and takes the last of his painkillers in an overdose for an edge against Kruger's team. Kruger meanwhile bolts on a more advanced, military grade exoskeleton and rampages through Elysium's central command looking for Max, while his men assassinate most of Elysium's leaders. As Max and Spider reach the main control hub, they are ambushed by Kruger, who fights to disable Max's exoskeleton and render him powerless. Max finally turns the tables, disconnecting Kruger's exoskeleton. Desperately, Kruger attempts to kill Max in a
murder–suicide using a grenade, but Max breaks free and throws Kruger over a ledge. The grenade detonates, killing Kruger.
Spider and Max lock themselves in Elysium's main datacenter and prepare the reboot as Patel leads a group to detain them. Max radios Frey to say goodbye, reminding her of a promise he made when they were children, that he would get them up to Elysium someday. After Spider configures the data changes, Max activates the program, killing himself. The computer core is rebooted with Spider's modifications, registering every Earth resident as a citizen of Elysium. Matilda is now recognized and cured by the Med-Pod Frey was able to find, and Patel, upon breaking into the core, finds himself powerless to stop Spider, as the android sentinels now recognize him as a citizen and refuse to arrest him. As a massive number of new citizens on Earth are now recognized by Elysium's main computer as being in need of medical treatment, fleets of emergency medical spacecraft equipped with Med-Pods and medical droids are dispatched to Earth and begin their work.
