Cast

Main Roles

• Hwang Min Hyun as Yun Ga Min
• Han Ji Eun as Lee Han Gyeong
• Cha Woo Min as Pi Han Ul
• Lee Jong Hyun as Kim Se Hyeon
• Shin Su Hyun as Lee Ji U
• Yoon Sang Jung as Choi Hui Won
• Gong Do Yu as Lee Jun

Support Roles

• Ju Yeon U as Kim Sun Cheol
• Baek Seo Hoo as Ma Min Hwan (Yeonbaek Gang)
• Hong Min Gi as Park Geon Yeop (1st Year Student)
• Park Yoon Ho as Lee Hyeon U (Ji U’s Twin Brother)
• Kim Young Ah as Jeon Mi Hyeon (Ga Min’s Mother)
• Jung Jae Sung as Vice Principal
• Shim Yoon Bo as Na Tae Man (Detective)
• Kim Hwi Gyu as No. 173
• Ri Min as Dean of Students
• Jin Woo Jin as Kim Gyu Jin (Disciplinary Committee Member)
• Seo Min Je as Kang Tae O

Guest Roles

• Lee Jung Hyuk as Pi Yeon Baek (Ep. 1)
• Kang Du Hyun as Student (Ep. 1)
• Yang Joon Seok as Student (Ep. 1)
• Song Won Su as Security Guard (Ep. 2)
• Kim Min Ah as Hwang Mi Hui (Ep. 3)
• Lee Nam Gyeong as Young Lee Ji U (Ep. 3)
• Jo Yi Hyun as Young Lee Hyeon U (Ep. 3)
• Kim Dong Gyun as Hwang Do Gyun (Ep. 4)
• Kang Ji Yong as Young Lee Jun (Ep. 4)
• Cho Yi An as Young Anti (Ep. 4)
• Song Seung Hwan as Teen Lee Jun (Ep. 4)
• Kim Min as O Jang Ho (Yeonbaek Gang) (Ep. 4)
• Shin Seo Woo as Young Kim Se Hyeon (Ep. 4-5)
• Dok Ko Kwang as Pedestrian Thug (Ep. 4)
• Lee Chang In as Nam Sang U (Ep. 4-5)
• Ma Hyun Ji as Hong Jae Hui (Ep. 4-5)
• Seo In Geol as Jang Bi Hwan (Ep. 4, 7)
• Mo Geon Hu as Kook Gwan U (Ep. 4, 7)
• Kim Jung Young as O Jeong Hwa (Former Teacher) (Ep. 4, 9-10)
• Lim Ji Sub as Anti (Ep. 4, 10)
• Lee Ung Jae as Yoo Jun Min (Ep. 5)
• Lee Keun Wook as Kang Dong Su (Ep. 5)
• Lee Dong Gi as Eom Seok Dae (Ep. 5)
• Choi Ye Chan as Young Kim Ho Min (Ep. 5)
• Kyung Ki Hyun as Delinquent (Ep. 5)
• Lee Jae Yong as Delinquent (Ep. 5)
• Jo Seung Yun as Dean of Academic Affairs (Ep. 5, 9-10)
• Yang Hee Woo as Driver (Ep. 6)
• Kim Min Chae as Real Estate Agent (Ep. 6)
• Ko Gyeong Man as Hospital Employee (Ep. 7)
• Kang Yoon as Chae Seon Ho (Ep. 7-8)
• Park Jae Hwi as Kim Jae Seung (Ep. 7-8)
• Kim Nak Gyun as Chu Seong Wung (Ep. 7-8)
• Jeon Moo Song as Sun Cheol’s Grandfather (Ep. 7-8)
• Oh Han Kyul as Young Park Geon Yeop (Ep. 9)
• Seo Soo Min as Student (Ep. 9)
• Ma Jung Pil as Hui Won’s Father (Ep. 9)
• Kim Mi Ra as Hui Won’s Mother (Ep. 9)
• Park Jin as Bang Sang In (Ep. 9-10)
• Kang Ji Hoon as Anchorman (Ep. 9-10)
• Park Jun Hyuk as Teen Anti (Ep. 10)
• Lee Jong Wook as Park Jung Nam
• Park Jung Hoon as Heo Jeong Min
• Choi Seung Hoon as Teen Yun Ga Min
• Jang Sun Yool as Child Yun Ga Min
• Han Jung Hoon as Park Min Cheol (3rd Student)
• Park Jun Woo as Bully
• Shin Min Soo as Custodian
• Jang Eui Don as Superintendent
• Kim Young Woong as Se Hyeon’s Father
• Lee Young Joon as Yusung Technical Student
• Seo Dong Gyu as Yusung Technical Student
• Lim Su Hwan as Secretary (Ep. 9-10)
• Kim Sung Ho as Guard (Ep. 7-8)
• Jang Joo Young as Kim Ho Min

Cameo Roles

• Yoo In Soo as Chu Jae Hwang (Student) (Ep. 9-10)
• Lee Jong Hyuk as Pi Yeon Baek (Han Ul’s Father)