Never Let Me Go is built upon some fairly commonplace themes. Unrequited love, the pains of growing up, the burden carried by the underclass all get an airing in the film. At times it feels very conventional, very plain. It is a story on a carefully considered path and it will follow it dutifully. Relationships are set up then quietly explored, themes are introduced then plumbed exhaustively. The wrinkle is the presence of a science fiction element within the story. It’s not overt or boldly proclaimed; it’s a far cry from the sort of boldly drawn and fervently underlined world-shifting that usually typifies science fiction films, even those that are pitched towards a more cerebral, more serious sensibility than the average tricked up, laser-fueled action film in disguise. It’s just an added flavor to the film, almost an aftertaste.

That’s even more clear in Kazuo Ishiguro’s original novel. The 2005 effort is a lithe, gentle-hearted story steeped in the cloudy angst of directionless youth. It’s primary setting–the one that casts a shadow that extends over the parts of the book that don’t actually take place there–is an English boarding school, the sort of place where unnameable discontent is so thick it practically leaves a film on the tasteful wood paneling. The students there are told that they have a special purpose, a statement not meant to build self-esteem, but to impose a deadening sense of responsibility. Ishiguro conveys it all with a remarkable sense of being. The prose is clean and elegant, refined and probing. It feels like a world described rather than a world invented, even with the hints of technology that don’t reside our current shared society. Much of the novel is actually set in the past, heightening the sense of the actual. This has all been lived. This has all been done.

Screenwriter Alex Garland and director Mark Romanek try to bring those qualities to the screen. While they are faithful adapters, they can’t quite recapture the sleek beauty of Ishiguro’s work. It winds up a little cold onscreen with the absence of an effective way to dig deeply enough into the characters to touch the undercurrents of their emotions. That’s not to imply that the performances are somehow lacking. As was the case with last year’s excellent An Education, Carey Mulligan’s remarkable expressive faces adds endlessly fascinating layers to her character. Keira Knightley nicely captures the way a mean streak can be embedded deeply in an otherwise decent person. Maybe best of all is Andrew Garfield, who effortlessly captures the perpetual boyishness of his character, a natural result of living a life that’s been sheltered by the singular nature of his social role.

It’s not just a comparison to the superior novel it’s adapted from that makes Never Let Me Go feel like a good film that could have been, should have been great. Romanek’s pristine approach seems an attempt to signal the prestige of the story, but it imbues the film with an odd hesitancy instead. It’s a daring story that is told cautiously.