Guest Stars Seo Yi Ra as Sgt. Oh Soo Hyun Lee Kang Wook as Jung Yoon Ho Kim Min Ju as Oh Yoon Jin (High School) Park Jung Pyo as Insp. Yoo Kyung Hwan Cho Han Gyeol as Jang Jae Kyung (High School) Lee Sang Jun as Kim Woo Sung Park Jin Woo as Class Six Teacher Kwak Ji Sook as Director Kim
