The premise of In Time is that some time in the near future, the whole human race gets genetically engineered for immortality. Humans are born with a count-down timeclock on one forearm, reading 1 year, 0 days, 0 hours, 0 minutes, 0 seconds. It doesn't budge until age 25, at which time two things happen: you stop growing older, and the clock starts counting down in real time. One year from now, a programmed-in suicide will knock you dead; from the way everybody grabs their chest when it goes off, I'm guessing it implodes the heart. But if you can earn time, you can extend that indefinitely. If you can afford the health care, and you avoid violent death or accidental death, you can live forever. You earn time the way we earn money; a central mint issues time, jobs pay in time, people spend time to buy necessities and luxuries.
Will Salas (Justin Timberlake) was raised by his single mother; his dad, who used to be an illegal prizefighter, was (he finds out) assassinated for giving away his substantial winnings to the poor. You see, here's how they solve the overcrowding problem: each zone has a rated maximum population. Whenever the population rises above that, wages are cut and prices are raised until the poorest people in the zone, the least productive, "zero out," they run out of time. And as the child of a single parent who took out ruinous pay-day loans to raise him, and who had to beg her son for time as soon as his clock started up, Will has never yet, in the three years since he turned 25, had more than 24 hours on his arm. Until one night he meets a suicidal financial services executive who has been giving away his time all day, who is down to his last 116 years on his arm, and Will saves that guy from an organized crime gang. It turns out that guy wanted to find a gang like that and have them steal all his time; he's 105, he's tired of living, and (as I read his motivation), like the rich guy whose death kicked off the movie Soylent Green, his conscience is killing him. So after Will saves him, the rich guy gets Will drunk, and gives him all of his remaining time, leaving him a note: "Don't waste my time."
The Timekeepers think Will stole that time. And they're even more worried when they find out that Will, like his father, is giving that time away to poor people; the population control function of high inflation can't work if the poorest aren't allowed to die off. If (as is said repeatedly in the movie) anybody is to live forever, many must die, but not all of them at once. And the last horrifying realization is that the central bankers, who restrict trade and travel across population zones so that they can control wages and inflation on a neighborhood by neighborhood level, have a secret: blackmailing people to be productive has worked too well. The earth could sustain a much higher population than it does; technology doesn't have to have fallen back to 1970s levels. They just keep it that way because they like having things the way they are, with them living like immortal god kings off of the production of a vast wage-slave class. (As with nearly all dystopian SF, there is no visible middle class in In Time. I can't even make up my mind if one was implied by the map on the wall.)
As he infiltrates the rich-people's neighborhood, Will meets a girl his own age, the only-child daughter of the central banker for the city he lives in, Silvia Weis (Amanda Seyfried). She's the first to spot that however much time he has on his arm, he's from the ghetto: he does everything just a little too fast, as if he were still in a hurry. And she has always desperately wanted to meet someone from the ghetto, because she hates being rich. The rich have too much to lose, so they take no chances at anything, and she's dying of boredom. So she doesn't object at all when Will, ambushed by the Timekeepers at a party at her house, takes her hostage; she joins forces with him, the (if anything) bloodthirstier half of the partnership, trying desperately to rob her father of enough time to keep themselves alive, to keep Will's friends in the ghetto alive, and ideally to destroy the big-time bankers.
The movie makes very good use of the countdown-clock storytelling device. Characters we care about are constantly running almost out of time, either from sudden surprise expenses or dangerous gambles or outright robbery, and the system really is rigged to make it "impossible" for them to get more time before they zero out. Even (more or less) knowing the ending, I kept finding myself leaning forward in my seat, watching people's arms count down their last few seconds, wondering how in the hell they were going to save themselves this time, and really caring. It's a great trick, one I haven't seen this well done since the first act of Spielberg's remake of Always.
Timberlake's no genius actor, but the nearly one note performance he's asked for in here is entirely within his range; he really sells the idea that this is a man who is would grieve his many dead loved ones if he could spare the time, a man who ought to be crippled by survivor guilt like so many of his neighbors are (there are a lot of good minor-character performances in this), and would be, if it weren't for one thing: he just can not make himself give up. And Seyfried nails the rich goth-wanna-be thrill seeker role, the rapid mood swings that come from finally getting what she wants and being completely unprepared for the reality, of someone who knows that she has no business falling in love with her kidnapper but realizes that no, it's not Stockholm Syndrome and no it's not just his cause (which is more her cause, for most of the movie, than his, because he just hasn't thought that far ahead) and no she's not just using him -- this "not giving up" thing is pretty hot.
The movie's not for everyone. You really do have to just accept the flaky premise at face value, the way you treat faster than light travel in space opera, and not set out to try to poke holes in it; if you can't accept it as a storytelling device, you will hate this movie, as quite a few reviewers did. And the ending feels out of place, like it was bolted on from another script at the last minute; if somebody digs up an article to show me that they test-screened a version with a different ending, that audiences hated it, and that the studio made them reshoot a more optimistic ending, I will not be at all surprised. But it was every bit the movie I was hoping for, and more.