Cuckolded mother: "Your mother, my wife"

Izumi divorced her husband and raised her only son, Takeo. Although it was a typical "single-parent family," Takeo was growing up without any twists. One day, Takeo ends up going to a three-week study abroad. Izumi's care for her best friend Masahiko... Then an incident occurs at the Takashima family, where Takeo is absent. Her husband, who was supposed to have broken up, appears in front of Izumi and commits violent acts. Masahiko happens to be there and ends up saving Izumi...