After growing up together as a family, Ju-won, San-ha, and Hae-jun go to high school together. San-ha and Hae-jun are hot with the girls, causing Ju-won to deal with the onslaught of requests from the girls to deliver their love message to them. Meanwhile, Ju-won longs to live under one family name through adoption, which the others think is absurd. Later, Hae-jun catches a suspicious man taking photos of him.

A man visits Hae-jun at school and reveals that he is Hae-jun's birth father. Although Hae-jun is initially speechless, he feels relieved to learn that his father has not abandoned him. To find out more about his father, he and San-ha talk with Aunt Yi-hyun to gain insight into his father's character before meeting him in person and uncovering the reasons for his sudden return after all these years.

Ju-won feels exhilarated about going on a date with a boy who is good-looking and smart, but she soon gets disappointed by what he says to her. San-ha and his father are upset by an unwelcome visitor who reminds San-ha of memories he doesn't want to recall. A surprise present from Hae-jun's biological father brings about a conflict between Hae-jun and his colleague.