Let the Right One In (2008)

Oskar, a meek 12-year-old boy, resides with his mother Yvonne in the western Stockholm suburb of Blackeberg in 1982. His classmates regularly bully him, and he spends his evenings imagining revenge, collecting clippings from newspapers and magazines about murders. One night he meets Eli, who appears to be a pale girl of his age. Eli has recently moved into the next-door apartment with an older man, Håkan. Eli initially informs Oskar that they cannot be friends. Over time, however, the two begin to form a relationship, and exchange Morse code messages through their adjoining wall. Eli learns that Oskar is being bullied by schoolmates and encourages him to stand up for himself. Oskar enrolls in weight-training classes after school.

Earlier, Håkan stops and kills a passerby on a footpath to harvest blood for Eli, but is interrupted by an approaching dog walker. Eli is prompted to waylay and kill a local man, Jocke, making his way home after having said goodnight to his best friend, Lacke. A cat-loving recluse, Gösta, witnesses the attack from his flat but, in disbelief, decides not to report the incident.