Guest Stars Seo Yi Ra as Sgt. Oh Soo Hyun Yoon Sa Bong as Unit Chief Jeong Yeon Joo Yoon Na Moo as Park Joon Seo Lee Kang Wook as Jung Yoon Ho Kim Min Ju as Oh Yoon Jin (High School) Cho Han Gyeol as Jang Jae Kyung (High School) Park Keun Rok as Jeong Sang Eui Park Jin Woo as Class Six Teacher Yoo Hee Je as Gong Jin Wook
