After divorcing her abusive husband, Koichi, Aika Ino lives with her son, Kazashige. One day, while Kazashige is out, Koichi suddenly appears at their home, issues harsh demands to Aika, and violently assaults her. When Kazashige returns and sees his mother's distressed state, he comforts her—but Aika, seeking to fill the emotional void, clings tightly to her son and presses her lips to his.