In many respects Moon, Duncan Jones's first feature film, is the antithesis of the contemporary big-budget science fiction film. There are no explosions. The future is not sleek and colorful, but monochromatic and grimy. It's not a film about robots or aliens, but about being human: hairy, clammy, swollen, and flawed, but fascinating.

The film opens with a faux-advertisement for Lunar Industries, a corporation which fulfills Earth's power needs using helium-3 harvested on the Moon. It's the sort of toothless goodwill spot petroleum companies put out, so we know right away that the rest of the film is going to undercut its message. Which it does, but not in the broadly satirical way we might expect.

Meet Sam Bell (played by Sam Rockwell, who carries the film capably and without swagger), the only employee at one of Lunar Industries's harvesting stations, nearing the end of his three-year contract. The film—perhaps wisely—does not attempt to explain how the fusion technology to exploit He-3 became practical. It's the first of several questions that may cause more scientifically-minded viewers to throw up their hands in exasperation.  But Jones's focus is on Sam (or Sams—but more on that in a moment). When we meet him he is heavily bearded, his hair grown wild; the clutter of his humanity spreads across the station's institutional white surfaces. He grows plants in polystyrene meal containers and carves a model of his hometown with an X-Acto knife. His space suit is gray with dirt and his primary rover is grimy and cluttered. This is working class science fiction on a par with Alien's Nostromo: bright, but harsh, and not shiny.

It's clear that, when we meet him, Sam is falling apart emotionally. He's got just a few days left on his contract, and he's desperate to get back to his wife and his 3-year-old daughter. His transmissions to and from Earth are delayed by satellite troubles, so that all of his human interactions are carried on as if via DVR. His only company is an AI named Gerty (voiced, somewhat distractingly, by Kevin Spacey), which accompanies its conversation with smiley-face emoticons, an at first cutesy device which becomes unexpectedly affecting as the film continues. Sam's fragile state becomes acute when a hallucination causes him to crash his rover into one of the He-3 harvesters, crippling both vehicles. He fades out of consciousness, and the next time we see him he is waking up back at the station, too weak to move.

But something's askew, both for Sam and the audience. Gerty talks about an accident on landing; Sam's bosses at Lunar forbid him to leave the station. Suspicious, Sam creates a maintenance problem to fool the AI into letting him outside; but his usual suit is gone, his primary rover missing. He makes his way to the crippled harvester and finds, of course, himself, injured but alive.

Up until this point there are questions about the bad turns a film like this might take—is it going to be another story about space madness? Ghosts in space? Or perhaps an AI gone bad? For some a film about clones will also elicit groans, but Jones's approach is original in one important respect, namely that there is no original in this story. Both Sams are clones, a fact which they gradually come to accept, the elder with a sort of sidewise resignation, the younger with impotent rage. The scenes between the two—the one fresh and vital, the other suddenly frail and shaky—are seamless, questions of how-they-did-that pushed aside by their twin dilemmas, existential and immediate. A rescue mission is on the way to repair the crippled harvester, and when they find both Sams alive there is no reason to expect they will not destroy them in favor of a new clone.

Perhaps the most satisfying aspect of Jones's direction is his insistence on linearity and a tight viewpoint. Just as both Sams are trapped on the Moon, so are we the audience, and just as they are frustrated by their attempts to understand what's happening to them, so are we forced to get by on the information we're given. The tension is created not by giving the audience more information than the characters, but by ratcheting up the characters' need to know simultaneously with that of the audience. So when we learn that Lunar Industries is jamming communications to and from the station, or that there is a corridor lined with sleeping clones under it, we feel the same vindication and dread that both Sams feel. When we learn that the wife both Sams pine for is long dead, their daughter grown, and the real Sam Bell at home with her, we feel their loneliness and despair, particularly as Sam-1 further deteriorates. This, of course, is planned obsolescence, to guarantee that no clone should outlive their supposed 3-year contract.

At this point practical questions begin to press on the more interesting existential ones the film wants to present. Given, for example, that there are only twelve years between the real Sam's tenure and the time of the film, how is it that all the clones are fully grown? Is the expense of producing, transporting, and storing them truly practical, and what about the technology to implant Sam's memories and job skills? Does Lunar Industries' means of transporting He-3 canisters back to Earth really make sense? These and other questions will, I fear, cause some viewers to scoff at the film.

It's certainly not perfect. There are pacing hiccups, particularly at the beginning, and the ending strains credulity a bit too much. And yet there is much to like here. Rockwell's depiction of two characters who are not sure who or what they are, husbands who have never met their wife and fathers who had no part in their child's conception, is quiet but powerful. The two clones move from mutual resentment and even physical confrontation to something tender and brotherly, yet built on untruths. As Sam-1's health further fails, Sam-2 puts a stocking cap on him to keep him warm, but the hat's Lunar Industries logo is like a label stamped on a piece of property. When they sit together sharing stories that don't belong to them, that they know are just implanted experience, they are comforting each other with the most valuable thing they have—memories of a place better than they one they're in, even though they've never been there. They're telling each other stories to make their short, miserable lives a bit more bearable, which is of course about as human as you can get.

David J. Schwartz's fiction has appeared in numerous venues; his novel, Superpowers, was nominated for a Nebula Award. He lives in St. Paul and blogs at http://snurri.livejournal.com.