Eli is about twelve, and has been for over 200 years, ever since she became a vampire. We never find out much more about her past, but as of the present day, she's living a lonely life in a Swedish suburb, one day at a time. In the same apartment lives Håkan, a middle-aged man, who has reduced his life to serving Eli. Above all, Eli needs fresh human blood regularly. Håkan provides to his best ability, in exchange for little more than the occasional display of affection from Eli. Håkan's attitude isn't the work of any vampire magic, but of pure attraction.

From the book on which the movie is based we find out Håkan is a former teacher, who lost his job after his sexual interests became known. He became an aimless vagrant, until Eli appeared and took control of his life. The book goes into much more detail about the characters and their relationship. There is an in-depth comparison in an A.V. Club column.

Though technically centuries old, Eli has remained mentally a child, more or less. When she moves into the same building as Oskar, the two befriend. Oskar too is lonely. He's shy, bullied at school, and has a distant relationship with his parents. There are peculiar things about Eli, such as her being lightly clad in the winter, unusual manners, and the occasional faint smell of a corpse. Much more importantly, for Oskar, she's nice and seems to want his company.

Oskar is not yet old enough to think primarily of sex, but is certainly willing to have a girlfriend in his attractive age-mate. Eli however acts as if she has nearly forgotten what sex is, to say nothing of other human emotions. What Eli does understand is affection and friendship. One gets the impression it has been a long time since Eli last connected with someone like she now does with Oskar.

The depth of Håkan's devotion to Eli becomes apparent when one of his killings goes utterly wrong. He's about to be caught in the act, and knows his face can be traced back to Eli. In order to protect her, he pours acid on his face, rendering himself mutilated and unrecognizable. He's taken to the hospital, where Eli comes to see him. Håkan lets Eli drink from him before jumping to his death from the window.

Eli doesn't treat Håkan this way out of malice. She simply must get blood in order to survive, and it has been Håkan's choice to enter the arrangement. Eli is used to having to kill, but not so much that she'd not feel for her victims.

As much as a vampire movie, this is a story about friendship between two lonely and awkward preteens. Both facets work well, complementing each other. Lina makes an interesting vampire, in part detached from human life, yet still hungry for affection and companionship. Lina's voice is replaced with a deeper one, which is better suited for her somewhat androgynous character, but you won't notice the dubbing. She's easily the most interesting vampire actress of our times.