Sam Bell (Sam Rockwell, best known to genre fans as Zaphod Beeblebrox in the 2005 movie version of Hitchhiker's Guide to the Galaxy) is nearing the end of his contract with Lunar. He's been a faithful employee for three long years. His home has been Selene, a moon base where he has spent his days alone, mining Helium 3. The precious gas holds the key to reversing the Earth's energy crisis.

Isolated, determined and steadfast, Sam has followed the rulebook obediently and his time on the moon has been enlightening, but uneventful. The solitude has given him time to reflect on the mistakes of his past and work on his raging temper. He does his job mechanically, and spends most of his available time dreaming of his imminent return to Earth, to his wife, young daughter and an early retirement.

But two weeks shy of his departure from Selene, Sam starts seeing things, hearing things and feeling strange. And when a routine extraction goes horribly wrong, he discovers that Lunar have their own plans for replacing him and the new recruit would appear to be his clone.

Before he can return to Earth, Sam has to confront himself and the discovery that the life he has created, may not be his own. It's more than his contract that is set to expire.

During a recent interview Rockwell said that Kevin Spacey will be playing the voice of a robot in the movie.

He said: "We've got Kevin Spacey who's going to play the voice of the robot. Which is great. But it's just me, and there are a couple of supporting roles of people who do transmissions onto the space station. That’s a pretty weird movie. That's a lot of Sam. It's a lot of Sam for me to watch. There's no Anjelica Huston, Kelly Macdonald and Brad Henke [his cast members from Choke] in that movie, but we do have Kevin, thank god."

Moon is being directed by David Bowie's son Duncan Jones (previously known as Zowie Bowie). The film will be released sometime in 2009.