Yoon Chan-young

as Joon

as Su-ho

as Joon-young / Ji-geun

as Jong-wook

as Han Cheol

as Young In-soo

as Soo-chul (Young)

as Seo Young-joo

as Yi-heon/Kim Deuk-pal

as Seo Young-min

as Lee Cheong-san

as Gong Yoon Tak

as Self

as Self

as Ju Dong-myung

as Lee Ki Suk (A CIPA patient)

as Ko Min-jae

as Gong Woo-Jin (young)

as Young Wang Rin

as Kang Dong-joo (Young)

as Ddang-sae (young)

as young Hong Joo-won

as Park Ri-Hwan (15 years old)

as young Ryu Tae-oh

as Han Geu-roo

as Lee Woo Jin

as young Jung Sun-woo

as young Lee Jae-hee

as Self