To rescue his mother from his father's domestic abuse, Takeru arrives at a hot spring town with her. Kiriko, his mother, notices the inn's proprietress and manager giving them curious looks due to their age difference, but she relishes this rare moment of relaxation. One day, the proprietress senses the forbidden emotions between the mother and son and devises a scheme to bring them closer together, setting in motion events that plunge their relationship into deeper taboo territory.