Haku, a 26-year-old Chinese student studying abroad, meets Rion, a 13-year-old girl who is a follower of a certain alien summoning ritual, on a suicide buddy recruitment website. When Haku finds out that Rion has run away from home, he invites her to his house. Rion suffers from bulimia, and binge eats and vomits almost every day. Every time she surprises Haku, she will whimsically lie about having eaten a cigarette, which worries Haku to death. As these exchanges continue, the relationship between the two becomes increasingly sour.