If hell is other people, as existentialist philosopher Jean-Paul Sartre famously put it, then Sam Bell has the best job in the world: He leads a solitary existence on a lunar base, where he's the only human employee in charge of a mostly robotic-controlled installation that mines fusion energy from beneath the moon's surface. His only company inside the air-locks is GERTY, a cloyingly helpful AI-cum-robot (voiced unctuously, and with more than a little nod to H.A.L. of "2001," by Kevin Spacey.)

Yet Sam (played by a haggard-looking Sam Rockwell) thinks he's lonely: He pines for his wife and child back on Earth, and he's counting the days till his three-year contract is up and he can return to the blue planet. Sam's about to learn the truth of Sartre's dictum, though, when another person arrives at the lunar base, and — Sartre would love this — that other person is him.

Without giving too much away, it should be clear that Duncan Jones' directorial debut, "Moon," is a mind- bender worthy of Philip K. Dick, a gnostic piece of sci-fi that sets up a spurious "reality" only to have it dissolve before our eyes. Sam comes to terms with the implications of there being another "him" rather quickly; what's harder is when he realizes he doesn't really like the guy. Things spin out of control faster than you can say "I'm not a clone, you're the clone!"