**Cast**
Kim So-hyun as Lee Eun-bi/Go Eun-byul
Yook Sung-jae as Gong Tae-kwang
Nam Joo-hyuk as Han Yi-an
Jo Soo-hyang as Kang So-young
Lee Pil-mo as Kim Joon-seok (homeroom teacher)
Jeon Mi-seon as Song Mi-kyung (Eun-byul's adoptive mother)
Jeon No-min as Director Gong Jae-ho (Tae-kwang's father)
Kim Hee-jung as Cha Song-joo
Yooyoung (HELLOVENUS) as Jo Hae-na
Lee Cho-hee as Lee Shi-jin
Park Doo-sik as Kwon Ki-tae
Jang In-sub as Sung Yoon-jae
Kim Bo-ra as Seo Young-eun (dropped out of Sekang in episode 3)
Jung In-seo as Jung Soo-in
