Never Let Me Go is absolutely beautiful but also gut-wrenching. The 2010 film stars Carey Mulligan, Keira Knightley, and Andrew Garfield as a trio who meet at a boarding school when they're just children and eventually come to discover something horrifying about their once-peaceful existence. It's also based on Kazuo Ishiguro's novel of the same name, in case you want to read it (and freak yourself out further). The author's work appears twice in this list: he wrote The Remains of the Day too.