Five years after his biological mother dies, the father suddenly remarries. Whenever Ayaka Mochizuki is alone with her adult stepson, the stepmother masturbates standing up, tempts him with a sheer thong, and finally takes his virginity. At night, thunderous sex can be heard from the father's bedroom. Sweaty and insatiable, she uses her pussy and mouth to drain both father and son day after day until the family collapses.