Intelligent science-fiction is something of a rarity these days, the genre having been overtaken by loud, silly things that focus on technology (weapons, usually) rather than on how humans are affected by it. So “Moon” should be enthusiastically greeted by serious sci-fi devotees, because it’s a smart story, meant for grown-ups, that doesn’t spell everything out but isn’t maddeningly ambiguous, either.

In many ways, it’s a traditional futuristic sci-fi story, complete with a robotic-voiced ship’s computer that speaks in gentle, condescending tones. (Watch for a huge difference between this computer and HAL from “2001,” though.) Set sometime later in the 21st century, it’s set on the moon, where Sam Bell (Sam Rockwell) is nearing the end of his three-year stint mining helium for Lunar Industries, a company that has solved the Earth’s energy crisis by using the moon’s resources. Sam is the only human employee; the actual harvesting is done by machines with Sam merely overseeing it, aided by Gerty (voice of Kevin Spacey), the station’s computer. Back on Earth, Sam’s wife and young daughter eagerly await his imminent return.

But then Sam is critically injured while driving the lunar rover one day. He wakes up in the infirmary, being tended to by Gerty, with no memory of the accident. He’s up and around again in a few days, but Gerty is acting furtive and evasive. (The “body language” of the machine, including video-screen emoticons, is just one of the film’s sublime pleasures.) Curious, Sam drives back out to the crash site, finds the wrecked rover, and discovers that it still has an occupant — an occupant who looks just like Sam.

And I will tell you no more! While the film doesn’t rely on twists or surprises, per se, it does reward the viewer by parceling out information methodically and satisfyingly. You might figure out which sci-fi staple is being employed before anyone in the movie uses the word, but it doesn’t matter — the enjoyment is in watching Sam figure it out (and, even more, watching him figure out what to do once he knows).

It’s an impressive feature debut by British director Duncan Jones, working from a screenplay by Nathan Parker (his first film credit), both for its stylish production design and its avoidance of clichés. Many filmmakers with much more experience have made sci-fi films far less convincing than this one. Jones deserves praise for the special effects alone, which allow Sam and his Doppelganger to interact seamlessly. We’ve come a long way since “The Parent Trap.”

Yet for all its technical achievements, the film remains off-puttingly cold. Sam Rockwell, whose easy-going persona usually makes him instantly sympathetic, seems detached here, as if so caught up in the futuristic sci-fi milieu that he’s forgotten to be a real person. It isn’t a deal-breaker, mind you — I did like the film, and I think hardcore sci-fi buffs will absolutely love it. You know who you are.

B (1 hr., 37 min.; R, a lot of harsh profanity, some bloody violence.)