A voiceover describes the state of the world. A place where time has become currency. Thanks to scientific advances people can stop aging at 25, but it comes with a catch: after reaching 25 a person is genetically-engineered to live only one more year. The time is used as currency, you can earn more at work but you sell it for goods and other services. Once your time runs out, you die.
Will Salas (Justin Timberlake) is a young man living in Dayton, a poor ghetto in the southwest USA. He lives day by day, making just enough to pass each day sharing time currency with his perpetually youthful mother, Rachel Salas (Olivia Wilde). She is 50 today, but has two days work in the garment district, she gives Will 30 mins for lunch. They will celebrate when she gets back. Everyone has a luminous green digital clock on their arms, counting down. Will is generous and easily gives 5 mins to a young beggar girl, Maya.
On the way to work he buys a coffee, the price has just gone up. Walking to work they see dead bodies in the streets. Will works in a metal stamping plant, making shiny cassettes. After his shift he notices he is paid less, quotas have gone up. Will meets his friend Borel (Johnny Galecki) at a bar. There they see a man treating everyone to drinks and drawing attention to his arm, which lists him as having over 116 years. Will knows that the man did not belong to the ghetto and was likely to draw attention to himself. Sure enough the Minutemen, a criminal gang, shows up, armed and ready to forcibly take the man's time. The gang leader, Fortis (Alex Pettyfer) is actually age 75. Borel and the rest of the bar scatter but Will interferes and helps the man escape. The two flee from the Minutemen and eventually find an old building to hide in. The man introduces himself as Henry Hamilton (Matt Bomer) and tells Will of the time-is-currency system. It had been established as a means of population control after the advances made in anti-aging processes, but as people were still surviving. Inflation and lower 'wages' were designed to keep the population in control. This currency system also meant that the rich could live much longer then normal and essentially become immortal, while the poor died. Henry however is tired of living for so long, an indignant Will tells him that the rich basically did not deserve their time. He tells Henry he doesn't want his time. Unwilling to abandon the depressed man, Will offers to stay with the man until the morning. At dawn, Henry passes his time to a sleeping Will.
Will wakes alone, with the 116 years of time and a message telling him not to waste it. Through a window, Will sees Henry seated on the edge of the bridge and realizes the man plans to commit suicide. He runs out to stop him, but just misses him as Henry's time runs out and he falls into the storm water channel. Will sees street cameras recording him and runs back home.
Will meets Borel with his family, and shows him his new time. To thank Borel for being his friend for so long, Will gives him a decade. Borel warns him that staying in Dayton with that much time was going to get him killed. Will wants to take his mom to New Greenwich.
Rachel pays off a 2 day loan at a Weis ATM machine. Sh tries to board a bus to get home but the fare has gone up to 2 hours and she has only 90 mins left. In a panic she has to run. Will is waiting at the bus stop, realizes something is wrong and runs toward Rachel. They meet somewhere in between, but too late, the mother dying in the son's arms. Later Will calls a private stretch Lincoln limo to pick him up and take him to a richer Time Zone. He passes through 4 toll booths with progressive fares into a gleaming modern but sparsely populated City center, New Greewich. He has cleaned himself up to dine at a nice restaurant, a young lady across the room takes notice. The waitress tells him to slow down, to blend in with the rich, and suggests a casino nearby.
Meanwhile, Henry's body is discovered by the Timekeepers, a body of authority much like the police. Raymond Leon (Cillian Murphy) notices the street cameras and examines the footage. When he expresses surprise at seeing Will's photo, his colleagues ask him if he knew the suspect and whether or not he had a criminal record. Raymond corrects them, telling them he did not know the current Will Salas but he did know the senior Will Salas. Timekeepers are mobilized to locate Will Salas.
At the casino, a tuxedoed Will meets Phillipe Weis (Vincent Kartheiser), arguably the richest man in the world. At a high stakes poker game, Will goes all in and comes out as victor, now with over 1000 years. Phillipe is impressed, as is Sylvia (Amanda Seyfried), his beautiful but sheltered daughter, the girl from the restaurant. Phillipe invites Will to his mansion for another party, and partially to see Sylvia again, Will agrees. Knowing to be prepared, he purchases a Jaguar E type and drives to the Weis mansion on the coast. There Phillipe reintroduces him to Sylvia, as well as his wife Michele (Bella Heathcote) and mother-in-law, all three of whom look the same age due to their wealthy background. The women are followed by guards all the time, but Will convinces Sylvia to let loose and have fun. Feeling oppressed by her father and his men, Sylvia agrees and the two go skinny dipping in the ocean. Sylvia admits wishing that she could often do something wild and crazy. Phillipe had always restricted his family members though, and sure enough he soon comes looking for her. Sylvia and Will manage to dress and make themselves presentable again when the Timekeepers appear and confront Will.
Raymond arbitrarily takes back the 1000 years as they don't believe Will's story. Raymond hints he knew Will's father and leaves. Will fights off the other Timekeepers and takes Sylvia hostage, escaping out the mansion. Raymond commits himself to chasing them, even taking personal risks that other Timekeepers avoided. After a car chase, Will manages to throw Raymond off their trail and escapes back to the country with Sylvia, who pleads to be let go. As soon as they return to Dayton the car is wrecked in a trap set by the Minutemen. While Will and Sylvia remain unconscious, the Minutemen discover that Will only has a little time left and was thus worth nothing, Sylvia however had about a decade and so they take hers instead. The men are forced to run before they could take all her time, Sylvia panics because she has never been reduced to having so little time. Will tells her that she should not be worried, as regular people live day by day. Instead, he brings her to find Borel, hoping that he could give them some time. To his grief, he learns that Borel had drunk himself to death with his riches leaving his wife and newborn alone.
Will manages to buy them more time by pawning off Sylvia's diamond earrings, but knows it isn't enough. He calls Phillipe and demands a 1000 year ransom for Sylvia's return, to be sent to the time welfare office. Raymond listens to the call and warns Will not to follow his father's path. Will learns that his father's crime was not stealing time but "something much more serious". Raymond, deduces where Will was hiding and assures Weis he would bring his daughter back safely. At Will's apartment he explains his father was an arm "fighter" with a trick to win time contests, he demonstrates that you let the other win at first, they get overconfident and distracted just as the last few seconds run down, then the arm can be flipped and the flow reversed.
The next day the ransom is unpaid, Will says to Sylvia that it was likely because her father was prevented by the Timekeepers but Sylvia saw it as proof that her father didn't care about her. Nevertheless, Will decides to let her go and tells her to make a call to her family. Since they were in the ghetto after all, he also gives her a gun to protect herself. They kiss and just as they split so that Sylvia can make her call, Raymond appears and nearly shoots an unsuspecting Will. A panicked Sylvia shoots Raymond instead, and Will corners Raymond and attempts to take his time. Raymond however has very little, for it is Timekeeper practice to carry only a little time to avoid being targets. Since Will was planning to take Raymond's car he graciously transfers 4 hours of his own time to him before hijacking the black Challenger car and leaves him alone in the ghetto.
Sylvia realizes that using a police car was essentially asking for attention. They end up robbing another limo and passenger, a blond woman dressed like a hooker. They learn that they had both been placed on a wanted poster with a reward of ten years to anyone who could bring about their arrest. Phillipe studies a large map of the world with colored lights and numbers, he assures his business partners that his daughter would not crash the current economic system. An injured Raymond manages to escape the ghetto, verbally harassed the whole time, and meets with Phillipe. Weis attempts to bribe Raymond into 'rescuing' his daughter but Raymond tells him that due to Sylvia's actions, an arrest warrant will be placed for her as well. If Phillipe interferred and tried to save his daughter, Raymond will see him arrested as well.
Will trains Sylvia how to use a handgun, she offers to help him get time. Will and Sylvia drive an armoured car through a Weis bank window and scoop up many time cassettes. They invite the onlookers to grab what they can also. The large status board shows the imbalance. This endears them to most people in the ghetto. Weis watches the news report of the robbery as his wife chides him for suffocating them. In a motel the two get closer, then sense something is up and just manage to escape Ray and his squad. Ray alone takes after them over rooftops in a running gun battle, refusing to let them go. They manage to bribe a bus driver and escape.
At a seedy hotel they rent the whole building for privacy. Fortis and his gang roust civilians until one admits where he saw the two runaways. In the hotel room the young couple describe how each went through the change at age 25 when the green numbers begin counting down. Fortis arrives and explains it is not just the rich and the Timekeepers oppressing the normal citizens, the Minutemen are being allowed to do so as long as they did not start preying on the rich as well. Fortis challenges Will to an arm fight to the death, as the two men lock arms together Will's time runs down fast. Will uses his trick to reverse the flow, then manages to pull a gun from his boot, kills the henchmen and times out Fortis. Will is dismayed and figures it will take a million years to change the system. Sylvia knows where they could find that time.
Sylvia returns home, pretending to turn herself in, distracting her father and his multiple guards, so that Will could sneak up on him. Under gunpoint, they take Weis to his office and open a large vault where they find a single cassette with 1 million years. Phillipe tries to say it is always in an individual's interest to live forever even at the cost of another's, but the two runaways are unconvinced. After locking Phillipe in the office the two again return to Dayton. While keeping the Timekeepers distracted, they pass the one-million cassette to Maya, the little girl.
Raymond pursues Will and Sylvia to a remote area running toward Livingstone, the next town over, just as they all begin to run out of time. Will sees that Ray is a Dayton homeboy, an honest cop just doing his job, but the timekeeper has forgot to get his per diem and dies in front of them as he times out. With only seconds to spare Will notices the police car in the distance, runs and manages to transfer the timekeeper's per diem from the centre console device to himself. He runs back to Sylvia and just manages to transfer some time, saving her life. The two of them only have enough for a day.
The Daytons stop work and march toward New Greenwich. Watching the news, the Timekeepers decide that their jobs are finished. With 100 years bounty on them, pulling up in front of a large institution, Will and Sylvia draw their guns to make their biggest heist.