It's 2044 and Joseph Gordon-Levitt (Young Joe) is an assassin in a rarified position: he's a "looper," a specialized breed that executes people from the future who are marked for death by gang leaders. Bound and gagged, the victims materialize and are shot by blunderbuss-toting killers who then collect bars of silver for their work. Their employment ends when their future selves are sent back through time -- with gold bars strapped to their backs -- to be killed by their younger selves, closing the "loop."

Inevitably such a complicated arrangement produces chaos. When Young Joe runs into his future self (Bruce Willis) he is convinced not to close the loop while Old Joe hunts down and kills the person who will one day become the inventor of time travel -- and the head of the syndicate that uses it for disposal. Old Joe is hell-bent on changing the future, and he won't let anyone stop him, not even Young Joe.

Looper is multi-layered, stylish and sleek, and filled with great action, setting a frenetic pace even in its still moments. Operating under a welter of influences from Twelve Monkeys to Terminator, it still manages to be intriguing. An enormous amount of action is achieved with very few special effects. The futuristic world is believable precisely for its sparseness, looking and feeling as stripped down and cheap as life itself is.

Although the movie runs long with a somewhat erratic third act, it's still engrossing and effective, not really adhering to good science but trying to say things about fate and chance that are worth thinking about. The loose premise requires strict adherence to the bargain in which most sci-fi fans and knowing film fans engage: a complete suspension of disbelief. Time travel is problematic even when all the particulars are worked out, and since all time-travel movies are essentially about the problems caused by re-working the past, perhaps it's just best to enjoy the story. In Looper, science is the medium, not the message. The tight focus on character, plot and dialogue cover any weaknesses in the plot.

Original enough to be both a cult film and an example to follow, while still being a subtle homage to its predecessors, Looper sustains its mind-bending ambitions while retaining its intriguing premise and impressive message, not about the mystery of time travel but the nature of self-sacrifice and the power of love.