Lately, Jun, an adolescent son, has been obsessed with his stepmother Yurina's huge breasts. Taking advantage of the fact that his father will be coming home late again today, he sneaks a peek at Yurina naked while she is taking a bath... Yurina sighs and looks up into the air, then begins to rub her voluptuous breasts and lewdly grope her crotch... Jun makes a noise in surprise and excitement, and tries to run to his room in a panic, but Yurina notices him...