Yu, a mother who has been raising her only son Yuu since the loss of her husband, decides to remarry her ex-husband's boss, Tamotsu. However, Tamotsu's stepchild, Yuki, has reached marriageable age and is excited by Yu's attractive adult body. By chance, Yuki witnesses Yuu providing sexual relief to his own son, and his desires are completely unleashed. "I want to take a bath with you," Yuki says to Yuu,"do the same for me." In the midst of this unusual love triangle, Yuu deepens his forbidden affair with his stepchild...