Living together with her stepson Mamoru, Chiaki's life takes a dark turn one day when he is absent and she is assaulted by his friends. Overwhelmed with sorrow, she wonders why she has been subjected to such a cruel fate. As the abuse continues, Chiaki gradually begins to awaken to physical pleasure, her body responding in ways she never expected. By chance, Mamoru witnesses her shameful state and approaches her with a look of shock—yet his words surprise her completely.