After a swim class, the girls find that only bras and underwear of C-cup girls and above are taken from the locker room. Ikkou is the prime suspect is relentlessly question by the girls. A friend of Ikkou, Yagani, reveals his feelings for Sumi and wants Ikkou to help him make Sumi instantly love him. The underwear thief is revealed to be a spirit and Jotoku orders the gang to exorcise the spirit after school. The spirit is Yagani and is exorcised after Ikkou awakens.