A few years ago, Junya lost his mother and lived with his father. It was at the end of the summer, just before Junya's entrance exams, that his father brought home his new wife, Mayu. For Junya, living with Mayu, who was too young to call him his mother, was a constant source of confusion and temptation. It was inevitable that a boy who had just hit puberty would suddenly become aware of his young stepmother as a woman...