The Transfiguration (2016) on Netflix

Plot summary

Milo is a fourteen-year-old who lives with his older brother, Lewis, in public housing in Brooklyn, New York. He believes himself to be a vampire, keeps a visual journal of the rules of vampirism he follows, and kills people to drink their blood, hiding the money he takes from them. On a walk he comes upon Sophie, a new neighbor, as a group of drunken teenage boys attack her; Sophie, an orphan like Milo, lives with a grandfather. After the boys leave, Milo leans toward the cut on her arm before she stops him. She admits she has thought about suicide, and he tells her he could not do that because it is against the rules. She finds him strange but endearing.