Imôto OL hitozuma: Sukebe marudashi.

Keita Sugisaki lives alone in Tokyo, and his stepsister Saori, who is about to take the university entrance exams, moves to the city from the countryside. He starts living with his stepsister, but one day, she comes to him for advice about a problem and they cross the line. After that day, for some reason, the number of women who try to seduce Keita suddenly increases.