The arrival of an intimate letter prompts a young woman to bring her mother on vacation to a small Japanese town, where someone special resides.

Dad who secretly raised the wedding because he didn't want to cheat on another woman. The daughter "Yeri" feels sorry for her mother who knows this, and recommends that her mother enjoy her life with a new man, just like her father. However, the perfectly normal (?) mother cannot organize her relationship with her father, and the father begins to beg for him to let go. Yeri set up a "Mom's Boyfriend Making Project" to make her cheat on her mom and starts interviews with men who will cheat on her.