Ha Jung-woo as Goo Joo-wol / Detective Ma Dong-wook

Gong Hyo-jin as Lee Hee-jin / Kim Hae-young

Yoo In-na as Soo-jung / Kyung-sook

Jo Hee-bong as Publisher Kwak / Detective squad chief Kwak

Lee Byung-joon as M

Ji Jin-hee as Goo Joo-ro

Kwak Do-won as Director Hwang

Seo Hyun-woo as Ui-Gyu

Son Byeong-uk as Juwol's Homeroom Teacher

Jeon Su-ji as art teacher

Choi Won-tae as Baek Sun-il

Kim Jae-hwa as Joo-hee

Park Jun-myun as Baek Sun-young

Lee Jun-hyeok as

Teo Yoo as Secretary

Kim Ji-hoon as Detective

Park Young-soo as Young-shik / President Jo