In Time (12A)

Starring: Justin Timberlake, Amanda Seyfried, Olivia Wilde

Final countdown: Justin Timberlake and Amanda Seyfried in the sci-fi In Time (AP)

Time is money, literally, in the high-concept thriller In Time. In a not-too-distant future that looks like an emptier Los Angeles, people wear a day-glo green clock on their forearm which starts a countdown once they reach a quarter-century. They stay looking 25, but from that point they have to beg, borrow or steal time to stay alive; from the number of people who drop dead where they stand this is clearly a tough ask. It's what one character calls "Darwinian capitalism", and the inequity of the disparate time zones – you're either time-poor in the ghetto or the tiny minority of time-rich in a protected metropolis called New Greenwich – offers a pretty straightforward comment on Planet Earth 2011.

One such ghetto-dweller is Will (Justin Timberlake), whose mother is just celebrating her 50th birthday. That she's played by the nubile Olivia Wilde indicates how nearly the film's conceit might have been played for laughs. When your mum looks like she could be your girlfriend there's no telling what hilarity may ensue. The writer-director Andrew Niccol is rather more high-minded, and explores his sci-fi premise much as he did with the idea of genetic perfection in his debut film Gattaca (1997). He follows to its conclusion Willem de Kooning's remark that "the trouble with being poor is that it takes up all your time": in this world not being able to afford a bus fare might be the death of you.

The plot kicks in when Will rescues a stranger from violent thugs in a neighbourhood where "they'll kill you for a week". The stranger turns out to be a) 105 years old; b) worth "centuries", and gifts Will his extravagant time-fortune before he, er, clocks off for good. So with his bank balance now refreshed a hundredfold, Will heads for the fabled time zone of New Greenwich, which looks a bit like Dubai without the traffic. Here, lunch with a tip costs (oo-er) nine and a half weeks, and a cool sports car will set you back five months. When he's invited to a swanky party by a time-owning billionaire (Vincent Kartheiser, from Mad Men) and takes the latter's vampish daughter Sylvia (Amanda Seyfried) for a skinny-dip in the ocean, the stage looks set for Will to indulge himself like... well, like a wannabe actor who's just sneaked through security and found himself partying with the beautiful people. For, if we're being cynical, In Time must be every Hollywood studio's dream: a film where the entire cast are made up of good-looking twentysomethings. Not an old person in sight!

Again, the comic possibilities are amusingly hinted at – the plutocrat introduces his wife, mother and daughter, and they might as well be sisters – but the film has more serious issues on its mind. A policeman, known as a "time-keeper" (played by Cillian Murphy), tracks Will down on suspicion of murder, and in classic fashion our hero goes on the run, his rich girl in tow. The early thoughtfulness wanes, and in its stead comes a very plodding sort of thriller. Will, you see, is out to challenge the system and right the wrongs of this grotesequely divided society. Not enough that he donates a "decade" to his feckless friend; he has to do the full Robin Hood and throw open the plutocrat's time-banks to the poor. In the becalmed atmosphere small things start to distract, such as the Betty Boop eyes of Amanda Seyfried, and the peculiarly awful acting of Alex Pettyfer as a thief who "cleans clocks" at gunpoint. Timberlake does a perfectly respectable job as the lead, without ever convincing you that the movie hasn't been a waste of the commodity it foregrounds.