Hinano is his wife's adult daughter from a previous relationship. He has lovingly raised her as his own, but today she finally brings a boyfriend home. Realizing she has reached that age makes him a little lonely, yet as a father he tells himself he will never stand in the way of her happiness. Then, while handing her a bath towel in the changing room, a dark desire takes hold. Before some unknown young man steals Hinano's virginity, he convinces himself that he must be the one to "protect" her.