Tsubaki lives with her daughter and son-in-law, and daily life has become increasingly strained by frequent arguments between the couple. One night, while sharing a drink, Tsubaki listens to her son-in-law vent his troubles. Drunk and overwhelmed, he suddenly pulls her into an embrace. Though initially shocked and resistant, Tsubaki gradually feels her emotions stir as loneliness and desire begin to awaken within her. From that night on, she starts secretly meeting her son-in-law behind her daughter's back. Though guilt-ridden, her body grows hot with passion, making it impossible to resist. As inner conflict intensifies, a forbidden new relationship takes root.