Aoi and her grandson Satoru live together alone. One day, Aoi falls ill and Satoru begins caring for her, deepening their intimate bond. Suddenly, Satoru's mother Eri returns after seven years away—the reason for her return is Aoi's inheritance. Realizing Eri's intentions, Aoi entrusts Satoru with her will. Eri then seduces Satoru, attempting to establish a new relationship. As the inheritance battle intensifies between grandmother, mother, and grandson, Satoru must ultimately choose his own path.