Casts
Song Joong-ki
as Wolf-Boy / Chul-soo
Park Bo-young
as Young Sun-yi / Eun-ju
Yoo Yeon-seok
as Ji-tae
Lee Young-ran
as Sun-yi
Jang Young-nam
as Sun-yi's Mother
Kim Hyang-gi
as Sun-ja
Yoo Seung-mok
as Professor Kang Tae-shik
Shin Bi
as Dong-mi
Woo Jung-kook
as Mr. Jung
Lee Jun-hyeok
as Policeman
