Upon hearing that their father, who had been living alone in the countryside, had fallen ill, three brothers return home. However, their father had secretly remarried—and his new wife is a young, attractive woman. The alluring stepmother, Saya, gradually draws the interest of each brother. Using their father's hospitalization as an excuse, the brothers begin pursuing their desires with Saya. The story unfolds as each of the three brothers deepens their emotional and physical relationship with Saya.