Young Dal and Ok Boon are parents to four grown children, Joon Seon, Ga Hee, Na Hee, and Da Hee. The two eldest ones live at home after getting divorced and the youngest is about to be married soon. The second daughter, Na Hee, is a pediatrician who is married to a colleague. She is the pride of her mother, but her life isn't as stable as it seems.

Na Hee's mother-in-law, Yun Jeong, barges into the hospital where both Na Hee and Gyu Jin work. She makes a big fuss about Na Hee being rude and ungrateful which doesn't help the couple's already rocky relationship. On the day of Da Hee's wedding, Gyu Jin arrives very late. After the wedding, Da Hee receives a big shock from her new husband.

Ok Boon is in an uproar as Da Hee refuses to explain why she wants her marriage annulled. Meanwhile, Gyu Jin's insensitive attitude bothers Na Hee, but she still wants to try to have a baby with him. She asks Gyu Jin to meet her at the fertility clinic, but Yun Jeong's drinking habit gets in the way. Na Hee looks back on her relationship with Gyu Jin.

Na Hee runs into Hyun Gyung, her brother's ex-wife, at the hospital and asks why they got divorced. Hyun Gyung's answer keeps replaying in Na Hee's mind. Meanwhile, Ok Boon goes to see Young Hoon and asks what happened between him and Da Hee. While his rude attitude helps Ok Boon to accept her daughter's wish for an annulment, the Song siblings band together to support Da Hee.

After realizing that Gyu Jin resented her all along for her miscarriage, Na Hee asks for a divorce. However, she wants to keep it a secret until her family gets over Da Hee's annulment. Meanwhile, Da Hee works hard to get hired as a full-time employee at work, but things don't go according to plan.