Milo steals money from a family he kills and gives it to Sophie so that she can run away to live with her relatives in another state. He then decides to commit suicide because he will never stop having homicidal urges. Milo tells the cops the identity of the men who shot the drug buyer and is killed by their gang in retaliation.
Milo (Eric Ruffin) is an odd teenager living in New York City. His father passed away and his mother committed suicide not long thereafter. He is being raised by his older brother who returned home from military service and spends his entire day sitting on the couch watching infomercials. Though the brother genuinely cares for Milo, he doesn't really know how to connect with him. Milo is also constantly harassed by members of a local gang who live in his apartment complex.
What nobody knows is that Milo believes himself to be a vampire. Once a month, Milo hunts down a homeless person or drifter, kills them by slitting their throats with a penknife, and then drinks their blood. That said, he has no vulnerability to sunlight or garlic or other traditional things that hurt vampires. Nor does he possess supernatural abilities. The movie never fully states whether he is a vampire or simply troubled.
He meets a teenaged girl named Sophie (Chloë Levine) whose parents have also died. She has been forced to move into Milo's apartment complex to live with her abusive grandfather. Sophie is not put off by Milo's off-putting nature. They discuss their dreams and Sophie confides that if she had enough money, she would leave New York to live with her kind relatives in another state.
Milo lures a drug purchaser to the basement of his complex under the pretext that he can buy drugs there. The purchaser runs into the gang members in the basement and they murder him. Milo is questioned, but does not tell the police what happened. During another hunt, Milo stalks a man he observed beating a woman. After breaking into the man's home, he is surprised by and kills the man's young daughter before killing the man as well. He steals all the money and valuables from the apartment, but seems regretful that he killed the innocent daughter. Sophie discovers Milo's journals and learns that he has murdered people and believes himself to be a vampire. Though she stops seeing him for awhile, the couple eventually reunite.
Milo asks Sophie on a real date. Although they have fun, Milo fantasizes about murdering her. At the end of the date, he gives her the money he stole so she can leave for her realtives' house. When she asks him to come, he says he can't because he will never overcome his murderous nature. Milo then plants the valuables he stole with the gang and goes to the police station and claims the gang killed the drug purchaser and the family Milo killed. The police arrest the gang members and find the stuff Milo planted there to make the case ironclad.
As Sophie leaves on a bus, she reads a letter from Milo. He notes that vampires must always kill and that he no longer wishes to do it. He expresses a belief that vampires cannot commit suicide, but they can set it up so they are murdered. By being killed, he will be released and the world will be a better place. As she reads this, Milo is shot dead by the other gang members in retaliation for his going to the police.