It's tempting to shorten a review of Never Let Me Go to four words ("read the book instead"), but a few things need to be said about what is surely the most romantic bioethics movie ever made.
Never Let Me Go (rated R for some sexuality and nudity) at first appears to be a proper boarding school story about children at an academy in rural England called Hailsham. Kathy (Carey Mulligan) has nice classmates and good teachers, and she is gradually learning about friendship with Ruth (Kiera Knightley) and love with Tommy (Andrew Garfield). And yet there are no parents anywhere, and the adults who aren't teachers at the school seem strangely put off by the kids.
Hailsham, briefly, is a boarding school in name only. It is actually an organ farm, a place where the clones of healthy people are raised to maturity, whereupon their major organs are harvested to benefit the rest of the world.
Never Let Me Go is not the story of how Kathy, Ruth, and Tommy escape this oppressive system. Instead, it's a very simple love story told by kids who are going to be murdered for the convenience of people who style themselves their betters.
The book, written by Kazuo Ishiguro, is subtle and affecting and communicates with great care just how human its heroes are, just how monstrous it would be to kill them, without ever saying so outright. The book is a masterpiece, and the film needs a better screenplay to be effective (this one is a rare misfire by Alex Garland). There are all kinds of great textual themes running through the book, and there's no visual correspondent to those in the film, so it bores even as it horrifies.
But once it starts to occur to you that the metaphorical subject of the movie might be, say, abortion, or stem-cell research, it's very difficult to keep the notion out of your head as the narrative progresses. As a movie, it ain't that great. As a conversation starter, it's very good indeed. Oh, and read the book instead.