Hee-jin tells Jae-yeol what happened that night, thinking he would be embarrassed about it. However, Jae-yeol doesn't get startled by it, and he confesses his feelings again. Hee-jin is still in doubt, but unexpected events make her think about him again. Meanwhile, Yeo-reum, who is a popular sports announcer, comes to school, and it seems like she and Jae-yeol have a history.

Hee-jin and her friends find out that Jae-yeol and Yeo-reum were a couple a few years ago. Hee-jin doesn't show it to others, but she's bothered by it. Jae-yeol tells Hee-jin that there's nothing between him and Yeo-reum, and this makes Hee-jin relieved. Watching them, Ji-won gets confused about his feelings toward Hee-jin. Meanwhile, Yeo-reum comes to school to see Jae-yeol again.

Multiple misunderstandings build up between Hee-jin, Jae-yeol, and Ji-won, causing Hee-jin to believe that Jae-yeol still has feelings for his ex, Yeo-reum. Meanwhile, the campus bustles as the school festival approaches with the Confession Tree event, planned to be hosted by Yeo-reum.