In the future, humans will be genetically engineered to live to 25.

The wealthiest citizens — the ones who either "come from time," the way people used to come from money, or who have triumphed in this futuristic version of Darwinian capitalism — can re-up on their time clock, while others expire.

You might be 50, or 105, but you look 25, always.

"Hi, mom!" Justin Timberlake says to Olivia Wilde early in the new film "In Time." It's a sharp gag: She appears to be his lover, not his mother. Later in the film, a character introduces his mother-in-law, his wife and his daughter, and they all look like they just came back from an audition for "Charmed."

In this future, time is the new currency, spent and borrowed like money. Each person's forearm is digitally stamped with a glowing green countdown clock, displaying the time they have left. Woman A can gift Man B 30 minutes, or a day, by a simple forearm handclasp. The economy in this version of the future is subject to wild inflationary swings. Sample dialogue: "Four minutes? For a cup of coffee?"

The writer-director of "In Time," New Zealand-born Andrew Niccol, greases this nifty premise as best he can. (His previous films include "Gattaca" and the less well-regarded "Simone"; he also wrote "The Truman Show" and more recently wrote and directed the arms-dealing picaresque "Lord of War.") The little details keep clicking into place. "Around here, they'll kill ya for a week," someone says of the inner-city neighborhood, or "time zone," where Timberlake's Will Salas scrambles to stay alive.

Just before committing suicide, a wealthy stranger gives Will the gift of a century — literally, 100 years. The Javert-like emblem of the law, a "timekeeper" played by Cillian Murphy, suspects Will of murder. On the run, Will takes the daughter (Amanda Seyfried) of a heartless tycoon (Vincent Kartheiser) as a hostage. Soon she becomes his partner in gunpoint philanthropy, because he's dreamy and a pretty good fellow, and in time, "In Time" turns into the movie year's most sincere ode to the redistribution of wealth, led by Robin Hood and his Merry Moll.

Frustratingly, Niccol's technique isn't up to his premise. The movie offers roughly 60 minutes of story complication stretched out to 109. Even with the help of a crisp, cool nighttime and daylight palette offered by cinematographer Roger Deakins, the director lacks an energizing way with a simple action sequence, or a page of expository dialogue. I like a lot of the film despite its drawbacks; its violence isn't rote or numbing, and there's a simplicity and elegance to the digital-countdown effect. Niccol would likely benefit from a more aggressive editor, not because the overall running time of "In Time" is a chore, but because the internal rhythms of even the better scenes could use a little zap.

"In Time"

Grade: 2 1/2 out of 4 stars

Genres: Thriller

Running Time: 109 min

MPAA Rating: PG-13