A few years ago, Junya, who had lost his mother, was living in a three-legged race with his father. It was at the end of the summer, just before Junya was to take his exams, that his father brought Mayu, his prospective remarriage partner. For Junya, living with Mayu, who was too young to be called "mother," was a series of confusions and temptations. It was inevitable that a boy just entering puberty would become aware of his young stepmother as a woman...