Does this seem familiar? The plot of the Swedish film "Let the Right One In":
A fragile introverted boy, 12-year-old Oskar (Kåre Hedebrant), is regularly bullied by his stronger classmates but never strikes back. His wish for a friend comes true when he meets Eli (Lina Leandersson), also 12, who moves into the apartment next door with a man who is presumably her father. But coinciding with Eli's arrival is a series of disappearances and macabre murders—a man is found strung up in a tree, another frozen in the lake, a woman bitten in the neck.The connections between sociopaths and vampires are obvious. Sociopaths are sometimes described as emotional vampires, and modern day vampire covens seem to be all about the psychopath. Some think that the vampire myth originates from vampires. It makes sense: life-sucking, preternaturally powerful, charming, seductive, dangerous... and somehow always falling in love with or befriending normal humans. Hard to know why that is, but I hope all the vampire love will spill over a little onto the sociopaths.
Captivated by the gruesome stories and by Eli’s idiosyncrasies (she is only seen at night, and unaffected by the freezing cold), it doesn't take long before Oskar figures out that Eli is a vampire. Nevertheless, their friendship strengthens, and a subtle romance blossoms as the youngsters become inseparable. In spite of Oskar’s loyalty to her, Eli knows that she can only continue to live if she keeps on moving. But when Oskar faces his darkest hour, Eli returns to defend him the only way she can...
Based on the best-selling novel by John Ajvide Lindqvist, Swedish filmmaker Tomas Alfredson weaves friendship, rejection and loyalty into a haunting and darkly atmospheric, yet poetic and unexpectedly tender tableau of adolescence.