After living separately from her husband on a solo business trip, Yoko's only son Ken began to get worse and her heart started to hurt. Ken's personality, dissatisfied with everything and quickly fights, is also swayed by his classmates, and he is finally forced to rebellion. Ken was betrayed by his believing friends, and was shocked to transfer to his father's solo homework destination. However, the tragedy doesn't end there, and when Yoko is alone in the house, the chimes of the house ring out...