A female detective investigates the cause of a high school girl’s death and uncovers a disturbing truth.

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.

Hae-Soo moved to a small city where nobody knows her. There, she opens a cafe and starts a new life. One day, a customer and a high school student, Ye-Jin, gives her a hand during the cafe's busy hour. Hae-Soo then hires Ye-Jin to work as a part-timer at her cafe. They form a close bond while secrets and confused emotions linger in the background.