Yuki Fukuda, having lost her husband, decides to live with her daughter and son-in-law out of concern for them. Their peaceful daily life as a family of three appears calm on the surface, but Yuki's heart remains deeply unsettled. She harbors a secret—her past intimate encounter with her son-in-law, Kosuke, the husband of her daughter. Concealing this truth deep within, Yuki struggles with overwhelming guilt, yet finds herself irresistibly drawn to Kosuke. Torn between familial bonds and the burden of her hidden desires, Yuki is consumed by uncontrollable urges, forcing her to confront where her heart truly leads.