Finally people have found a better way to provide energy to the world by mining the moon for helium-3, helping to end the energy crisis. Astronaut Sam Bell is the sole engineer on the base supported by GERTY, his robotic assistant, and is finally coming to the end of his three-year stint.
With little contact with Earth, he's suffering from headaches and bouts of nausea, talking to himself, and seeing things. The only solace keeping him going are short recorded communications from his wife, and the hope of seeing her and his daughter soon. Then he crashes in one of the buggies while out checking a mining harvester. When he wakes, in a pretty foul mood, things begin to get weird after he finds GERTY having a seemingly live communication with the team on Earth. GERTY's not telling him the whole story, and Sam decides to investigate himself. Sam, literally, finds himself out in the wreckage of the buggy. Sam Bell.
Sam Rockwell is utterly absorbing in Moon as Sam Bell - or Sam Bells. Acting against a direct cast of one (himself) and the voice of Kevin Spacey as GERTY, Rockwell portrays on one hand a deteriorating, hallucinating man, losing the strength and health he's enjoyed in his (alleged) life while giving the planet he calls home better future. On the other hand he portrays a serious and unimpressed opposition to his ailing counterpart, with a rotten temper, looking down on the other Sam, and unwilling to accept any sort of bond between them that clearly exists.
The conflict between the lonely older clone, who has softened in personality, created a world for himself with this plants and his carved town, and the new clone, whose temper and attitude is very likely more similar to their original source, the true Sam Bell, allows Rockwell to explore two distinct versions of his character. The breaking down of Sam 1 is heartbreaking, but the gradual connections forged with Sam 2, who looks after his counterpart as he's dying, are beautifully realised by the wonderful writng, and performed brilliantly by Rockwell.
The other main character, GERTY, wonderfully portrayed by Kevin Spacey and the production design team, is the empathetic heart of the story. Being put there with one mission, to help Sam, GERTY has over time become attached to his charge, and when challenged by Sam 1 he does exactly what he's expected to do: tells the truth. Through Sam 1's pain and deterioration, GERTY continues to ensure he's looked after, helping him discover the background of what's happening. The helpful trait added by the designers of the clone program ultimately becomes the flaw in their organisation, and the downfall of the program, once GERTY's helpfulness is found not to stop when Sam 1 and Sam 2 need and request his assistance.
Moon is a brilliant character study of the recipient of the desperation of humanity and the unethical lengths some might go to when faced with a problem they're intent to solve. The isolation and processing of the clones, tucked away on the moon where nobody has to think about them but a machine, then shifted into storage when their use has been exhausted, exposes the terrifying rights some believe they have over others, whether those others are born of women or created in a lab. It also exposes an arrogance by the perpetrators of this fraud upon the poor clones, and the world in general, which might well be stopped in its tracks by the one victim it tried to silence.