A group of close friends who attend a private school all have a debilitating crush on the sunny star pupil, Sun-ah. The only member of the group who claims not to is Jin-woo, but he ends up loving her as well.
| Actor | Role |
|---|---|
 Jung Jin-youngKoo Jin-woo | Koo Jin-woo |
 DAHYUNOh Sun-ah | Oh Sun-ah |
 DEMIANAhn Sung-bin | Ahn Sung-bin |
 Lee Min-gooByun Tae-wan | Byun Tae-wan |
 Kim Yo-hanOh Dong-hyun | Oh Dong-hyun |
 Kim Min-juYoon Ji-soo | Yoon Ji-soo |
 Lee Seung-junHan Byeong-ju | Han Byeong-ju |
 Hwang Gyu-chanYong-rae | Yong-rae |
 Park Sung-woongJin-woo's Father | Jin-woo's Father |
 Shin Eun-jungJin-woo's Mother | Jin-woo's Mother |
 Jo Dal-hwanTechnology and Home Economics Teacher | Technology and Home Economics Teacher |
 Shin Gi-ruGeography Teacher | Geography Teacher |
 Lee Seon-minHomeroom Teacher | Homeroom Teacher |
 Son Woo-hyeonSun-ah's groom | Sun-ah's groom |
 Lee Ju-seungSenior | Senior |
| CCho Jae-kyeongStudent | Student |
 You Eun-aStudent | Student |