Haruki Sato's character, Haruki, feels lonely due to her husband's neglect as he is consumed by work. She begins a secret affair with her brother-in-law, Katsuki. Through this relationship, she tries to fill the emotional void in her marriage. Meeting once a week, Haruki initially struggles with guilt, but gradually those feelings transform into genuine love for her brother-in-law. When Katsuki announces he must leave for an extended overseas business trip, he starts to seriously consider their relationship. However, Haruki desperately clings to him, deepening their forbidden bond even further.