It is Kyouya Sata's 17th birthday, and it seems Erika Shinohara has forgotten about her beloved boyfriend's important day. Even Erika's best friend, Ayumi Sanda, appears to be unaware as she asks Kyouya to tutor her after school. However, behind the scenes, Erika is preparing a surprise in Kyouya's apartment and has assigned Ayumi the job of distracting him. Not everything goes as planned, though, as in front of Kyouya's home, an unlucky accident sets Erika into a complete frenzy—meaning Kyouya now has to find a way to calm down his oddball girlfriend.