In 2003, in Manchester, England, a 16-year-old boy whispered the words, "I love you, bro" as he plunged a knife into his best friend, who nearly died but didn't. The bizarre series of events behind this crime inspired the acclaimed opera Two Boys and now Uwantme2killhim?, a compelling but ultimately unsatisfying film. Mark (Jamie Blackley, excellent) is handsome, popular and increasingly in love with Rachel, a 20-something girl who talks dirty to him in online chat rooms. (Remember those?) At Rachel's urging, Mark befriends her much-bullied brother, John (Toby Regbo). The two soon prove inseparable, even as Mark becomes obsessed with a new online friend whose sly manipulations ultimately drive him to murder. Director Andrew Douglas and screenwriter Mike Walden effectively jumble the film's timeline, opening with the crime, then jumping back to the beginnings of Mark's online life and then forward again, as a police inspector (Joanne Froggatt) tries to unravel the meaning behind Mark's assertion that he stabbed John "for the greater good." The filmmakers get the facts right, for the most part, but they're too busy protecting the third-act plot twist to truly ponder the essential question of this sad, weird story: Why did this happen?