Episode 1 S01 E01

Kim Sae-ron (as Jung Ah-rin) Cha Eun-woo (as Cha Eun Woo) Moon Bin (as Moon Bin) Kim Myung-jun (as MJ) Park Jin-woo (as Jin Jin) Park Min-hyuk (as Rocky) Yoon San-ha (as Yoon San Ha) Seo Kang-joon (as Ah-rin's elder brother)

time travel friendship high school romance school boy band