Akiko moves into a school dormitory with her brother Akito, when he transfers to her school; owing to her brother complex, Akiko has a crush on Akito.

Akito catches Akiko reading a trashy romance novel; Akito, having trouble settling into his class, is given firsthand lessons in the concept of tsundere from both Akiko and Anastasia; Akito and his longtime friend Ginbe get into an argument.

Akiko asks Akito for help changing her light; Akito has his hands full maintaining the dorm, from fixing the plumbing to repairing the doors.

Akito brings home a special dessert, just for Ginbe to enjoy. Akito continues to fix up Anastasia's room.

In a student government meeting, the council members discuss what they are going to call Akito; Kaoruko proposes that Akito write a short story to be published in a women's magazine.

Kaoruko reads the latest installment of Akito's love story; she decides to stop by the dorm, where she meets the others, and asks them whether they think Akito has a sister complex; the council decides to separate Akito and Akiko into separate rooms.