Ji-woo, an outcast at a prestigious private school, meets Hak-sung, the school janitor who is actually a mathematical genius who defected from North Korea.
as Ri Hak-sung
as Han Ji-woo
as Ahn Gi-chul
as Kim Geun-ho
as Park Bo-ram
as Tae-yeon
as Park Pil-joo
as Professor Oh
as Bo-ram's Mother
as Ji-woo's Mother
as Korean Teacher
as NIS Agent
as Student 5
as Ui-joon
as Principal
as Hanbok Teacher
as Ddal-bong
