When a peculiar girl named Guri knocks on Seiji Aino's door, he is swiftly plunged into a realm of romantic complications. Asserting that she will perish if he fails to kiss someone within 24 hours, Guri's desperate pleas are misinterpreted as romantic advances, prompting Seiji to kiss the attractive stranger who had barged into his home. In reality, this cosplaying cupid wields a Kiss Note, wherein any pair of names she inscribes will kiss and become a couple. Guri explains that she misspelled and inadvertently wrote Seiji's name while indulging in her yaoi fantasies, but since she had not yet paired him with anyone, their kiss held no meaning. To make matters worse, Guri reveals that if Seiji is not coupled with someone soon, not only will she die, but Seiji will remain a virgin for eternity. Eager to escape his fate, Seiji sets his sights on the beautiful and popular Akane Hiyama. However, after Akane learns that he kissed Guri, she exposes the obsessive and psychopathic feelings she harbors for the unfortunate boy and proceeds to viciously attack them. Amid the ensuing confusion, Guri manages to pair Seiji with Akane in the Kiss Note, temporarily sparing Seiji from further physical harm. But to complicate matters, Guri's newfound feelings lead her to also pair the two of them with herself. Just when the situation could not become any more convoluted, this new coupling with Guri transforms Seiji and Akane into temporary angels, forcing them to assist the cupid with her work of pairing humans, lest they be cast into hell. With all semblance of normality stripped from his life, Seiji begins matchmaking with these eccentric girls by his side.