Ani Tomo (Brother’s Friend)

Sota Nishino (Ryusei Yokohama) is a handome high school boy. One day, he is invited to his friend Yukihiro Nanase’s house and meets Yukihiro’s younger sister Mai Nanase. Mai is a naive and old-fashioned girl who loves to do household chores. Sota mutters to Yukihiro “Your sister is cute.” Mai overhears it through the thin wall between her room and her brother’s room.