Three weeks. That is all Sam Bell has left on his three-year contract when Moon begins, and he wants to go home. He mines helium-3 on the far side of the Moon for Lunar Industries, and his only company is GERTY, the base’s computer assistant, voiced by Kevin Spacey. Duncan Jones, making his directorial debut from a story of his own that Nathan Parker turned into a screenplay, builds the whole film on that solitude.

Live contact with Earth is down, so Sam gets recorded messages and little else, some of them from his wife Tess. Then he starts seeing a teenage girl who is not there. One of these visions distracts him while he is out recovering a canister, and he wrecks his rover. He wakes in the base infirmary with no memory of the crash. Something is off, and neither GERTY nor the company seems willing to say what. I will not spell out the rest. But the central reveal, that there is more than one Sam Bell, is hardly new to science fiction. Jones treats it as a question of feeling rather than plot machinery, and that is why it lands.

The film’s strength is how little it has. The base is small and the cast is smaller. The New York Times, reviewing it, noted that outer space in something like Star Trek or Battlestar Galactica can seem awfully crowded; Moon is the opposite, and the emptiness does much of the work. Clint Mansell’s score keeps a quiet, insistent pulse under the isolation without ever telling you how to feel. The modest budget reads less as a limitation than as a choice of style.

Sam Rockwell carries all of it. The Guardian called him very good and was glad to see a major role go to such a distinctive, engaging performer, and Rotten Tomatoes singled out the intensity he brings. Both are right. He shows a man who is tired, confused and, at moments, plainly furious. The scenes in which two Sams share the screen are the best in the film. Rockwell plays against himself, shading the two men differently enough that you always know who is who, and the argument that turns physical feels dangerous because neither man has anyone else to turn to.

Spacey’s GERTY is a smaller and stranger part. The voice is calm and measured, which sits uneasily beside Sam’s growing suspicion. GERTY is the only voice Sam has to talk to, and Spacey makes it warm enough that you want to trust it and unsettling enough that you cannot quite say whose side it is on. I found the relationship interesting, though at times more predictable than the rest of the film.

Then there is Lunar Industries, and here the film gets angry in a very quiet way. Sam’s discovery of hundreds of hibernating clones is the coldest moment of the story. It does not need a speech. The company has found it cheaper to reuse one man than to train and transport new ones, and the film lets that sink in through what Sam sees and what it does to him. The human cost is what stays with you, not the premise.

It is not flawless. The first act is patient to the point of dragging, and the hallucinations and the accident take a while to set the story moving. The resolution, after all that built tension, feels hurried. Tess, and Eve, played by Kaya Scodelario, stay at the edge of the story, and we know them only through messages and glimpses. Given how tightly the film is focused on Sam, that is understandable, but it is still noticeable.

Moon premiered at Sundance in 2009 and opened in New York and Los Angeles on 12 June that year, reaching more American theatres on 10 July and the United Kingdom on 17 July. It grossed just under $10 million worldwide on a modest budget, won the Hugo Award for Best Dramatic Presentation in 2010 and was nominated for the BAFTA for Best British Film. Jones later returned to its world with Mute, released in 2018 and containing an epilogue to the story, and the graphic novel Madi: Once Upon a Time in the Future followed in 2020.

The twist can be spoiled in a sentence. The loneliness cannot, and that is what you take away from the theatre.