"Never Let Me Go" is a touching, thoughtful, sublimely acted prestige drama based on a fantasy premise. In Kazuo Ishiguro's bestseller, a 1952 medical "breakthrough" revealed a method of reversing once-incurable diseases and extending the average lifespan to 100 years. But it requires organ donations. Lots and lots of them. Forty-some years later, it's one of society's awkward little inequities that a special class of children are bred to supply replacement parts for their elders.

Similarly themed films, such as "Logan's Run" and Michael Bay's "The Island," treated bioethics as the starting point for bombastic games of laser tag. "Never Let Me Go" belongs to a higher-minded category of entertainment; think Merchant Ivory sci-fi. It doesn't set out to pummel your senses, but to stimulate thought and send little shivers up your spine. And it succeeds completely.

Set in England, the film is told through the voice of Kathy H. (Carey Mulligan) who mingles memories of her youth with her current position as a "carer." Carers function as surrogate next-of-kin for "donors," compassionately visiting them before and after their operations, and signing the funeral paperwork when they "complete," usually after two or three surgeries. Kathy does her job with pride, awaiting the time when she will become a donor. The Orwellian euphemisms, the gentle totalitarianism of the medical establishment and the sheeplike acceptance of these outrages are quietly horrific. Anyone who protests that such things could never happen needs a refresher course on 20th-century history.

We move back in time to Kathy's education at Hailsham boarding school, where placid headmistress Miss Emily (Charlotte Rampling) methodically grinds down independent thought. Kathy, tenderhearted Tommy D. (future "Spider-Man" Andrew Garfield) and lovely, manipulative Ruth (Keira Knightley), form a youthful romantic triangle whose outcome may determine their futures. To say more would be to spoil developments that viewers should have the pleasure of discovering themselves.

The actors excel in revealing the passions buried within characters whose feelings have been intentionally stunted to ensure docility. Mulligan's achingly expressive face is the window into Kathy's sweet and gentle soul, while Garfield uses his gawky physicality to capture Tommy's trusting immaturity and his ultimate desperation. Ruth is the most complex of the three, maneuvering herself between the natural partners because she envies their connection. Knightley, often dismissed as a mere pretty face, demonstrates surprising depth and feeling in the role. We shouldn't be surprised; director Mark Romanek is a specialist in understated emotional violence. He drew out one of Robin Williams' finest dramatic performances in 2002's ominous "One Hour Photo."

The fate of the young characters could be read as a metaphor for any segment of society whose humanity is routinely denied, but this film is far more than a civics lesson in disguise. It asks us to consider deep questions about love and mortality and our docile willingness to walk paths that others have chosen for us -- "for our own good," naturally. "Never Let Me Go" is a bleak and heartbreaking cautionary tale about how we all behave before we "complete." How bleak and even how heartbreaking one does not realize until the devastating final scene. It deserves an honored place on the small shelf of philosophical science fiction alongside "Gattaca," "Children of Men" and "A Clockwork Orange," though it could not be more different.

Colin Covert • 612-673-7186