Having lost his mother at a young age, Masato lived with his father, doing housework between school. It was at the end of the summer, just before Masato was due to take his entrance exams, that his father brought home his new wife, Yuri. For Masato, who grew up in an all-male household, living with Yuri was embarrassing and a constant source of confusion. Her smell, her mannerisms, her gentle voice, her soft-looking breasts. It was inevitable that a boy who had just hit puberty would suddenly become aware of his young stepmother as a woman.