After retiring, Wagatsuma boards a crowded train in the morning, where he witnesses Mia responding to a man's caresses. When the man gets off, Wagatsuma reaches out to her body as if inviting him. Since then, he has not been able to forget about Mia, and while searching for her on the train, he meets Kitamura, who previously knew Mia. Kitamura teaches him the philosophy and rules of groping. One day, Wagatsuma's son, Kazuo, is arrested by the police for groping...