He went on a hot spring trip with his second wife and stepdaughters. While he and his wife were making out in the hot spring, his daughters joined them, and he was aroused by their large breasts and erotic bodies. The mischievous daughters played pranks on his erect penis while they bathed together. To seize a moment of solitude, the son and stepmother, and the daughters and stepfather, touched each other in the bath, eventually succumbing to forbidden penetration and entering into a taboo relationship.