Guest has had terrible luck with relationships, having been cheated on by every single partner so far. Convinced they have no eye for people and should never date again, Guest had resigned themselves to a life alone. That is, until Nagisa, a junior from high school, moves into the apartment next door. Despite having sworn off romance, Guest finds their heart wavering under Nagisa's persistent advances... To Guest, Nagisa appears to be a polite, charming young man, but his true face is that of a dangerously obsessed man who is utterly dependent on Guest...?