Sister and sister

Mizuho's boyfriend, Yoshiki (Ayumu Mochizuki), comes to stay at the house where her sister Mizuho (Misato Aoyama) and her sister Natsuki (Seina Nakata) live together. There is no physical relationship between the two yet. While Mizuho takes a shower, Natsumi tries to find out the relationship between the two from Yoshiki by digging roots and digging leaves. While saying, "I've thrown away my sister's virginity," Yoshiki continues to manage the onslaught of Natsuki, who actively seduces Yoshiki with "Sister, long bath and Nen." Eventually the shower stopped and the room door opened.