Naoki, a young NEET, is cornered by Nami, his childhood friend, who, driven by curiosity, has become obsessed with sex and tries to seduce him. However, Naoki rejects her advances because he is conflicted due to his secret relationship with Mizuho, Nami's mother. Jealous, Mizuho confronts him in the bathroom, seducing him with provocative movements. Although he knows he should stop this, Naoki can't resist the temptation.
