Contains spoilers for this episode and earlier episodes.
Su-ho finds a letter Se-yeon left for him and Seo-jun, thanking them for the happiness their friendship gave him. The boys visit his grave, apologize to each other and begin facing their loss together. Ju-kyung enrols in beauty training, but Hye-min's arrival at Saebom makes her fear that her past will emerge. Su-jin notices her discomfort and probes the connection between the two girls. When Ju-kyung rescues Hye-min from Sae-mi's bullying, she asks her to keep the past private. Su-jin stays behind with Sae-mi and arranges to exchange photographs of Seo-jun for pictures of Ju-kyung without makeup.
After winning a school popularity competition, Ju-kyung is surrounded by admiration while Su-jin continues her plan. She takes Ju-kyung's necklace and destroys it in front of Su-ho, asking him to break up with Ju-kyung and choose her. He refuses. Su-ho replaces the missing necklace, and an interrupted meeting at school exposes both his relationship and Hee-kyung's relationship with Joon-woo to the couples themselves. Elsewhere, Seo-jun confronts Sae-mi when the bullies approach Ju-kyung's home with her old photograph. He smashes the phone rather than join their ridicule. By the next school day, the images have spread among Ju-kyung's classmates. Their questions and stares send her running from the building, unable to face Su-ho.