It might not seem like a sci-fi thriller on the surface, but the deeper one goes into this drama based on a novel by Kazuo Ishiguro ("The Remains of the Day"), the clearer its genre-bending cleverness is.

Carey Mulligan, Keira Knightley and Andrew Garfield ( "The Social Network") make a dynamic trio as students kept rather cloistered at their private school. When they decide they want to see the world outside, the true nature of their shared existence becomes known to them. Veteran actress Charlotte Rampling also stars for director Mark Romanek. DVD extra: "making-of" documentary. *** (R: AS, P) (Also on Blu-ray)

Buy 'Never Let Me Go' on DVD.