Available on DVD: “Never Let Me Go”

“Students of Hailsham are special,” it is declared in Mark Romanek’s Never Let Me Go, a film more moving than most but not as devastating as it should be.

It’s best if you come to this story — adapted from Kazuo Ishiguro’s piercing novel — knowing as little as possible. So let’s just say that the children who reside at Hailsham, a British boarding school, are indeed unusual and not at all to their advantage. They are being groomed for lives unlike others, an ominous fate their headmistress (Charlotte Rampling) refuses to explain.

The students do have their pleasures, especially in friendships like the one between Kathy (Carey Mulligan) and Ruth (Keira Knightley). Their relationship is strained when Ruth begins dating Tommy (Andrew Garfield), the boy Kathy loves. But once the three leave for the outside world, they realize that whatever their differences, they’ll always need each other.

The film, set in the late 20th century, envisions a sci-fi nightmare in which humans have made life much easier for themselves — at great ethical expense. Romanek does an extraordinary job translating Ishiguro’s deliberate, almost excruciating pace onto the big screen: His images haunt us in much the same way the author’s words do.

Screenwriter Alex Garland also respects Ishiguro’s eerie understatement, rejecting easy shock value for a deeper, more horrifying calm. But he’s cut too much explanation, leaving gaps in logic. More frustrating is the superficial connection among the characters.

Mulligan’s deceptively passive turn is heartwrenching and should have earned her a second Oscar nomination. Knightley’s beautiful Ruth, however, is missing a soul, while Garfield’s unmemorable Tommy lacks any real chemistry with either woman.

The film’s flaws keep us at a regrettable distance. Though there are painful moments and beautiful ones as well, the end result feels more conceptual than real: a tragic notion, rather than a potential reality of unbearable sadness.