detective Kim Eung-soo as Kim Young-chul, head of investigation unit Park Eun-ji as Han Yoo-ra, Joon-hyuk's fiancée Kim Byung-se as Choi Jae-wook, deputy department head Shin Kwi-shik as Park Jin-woo, police commissioner Kim Sun-young as Joon-hyuk's mother Kim Byung-choon as Joon-hyuk's father Seo Ye-hwa as Lee Soo-jung, Joon-hyuk's younger sister Ha Gyu-won as Lee Ji-hyun Son Young-soon as Choi Jae-wook's wife Park Hyo-joo as Jeon Hye-jin Kwon Eun-soo as Guem Mae-sil Lee Ki-woo as Park Tae-min Lee Seung-ho as Jung Myung-ho Lee Tae-hyung as Charlie Jung Guest appearances Sam Hammington as Russian robber (ep 1) Kwon Mina as Han Seol-hee (ep 3, 6) Lee Yong-nyeo as Han Seol-hee's maid (ep 3) Kim Jin-soo as Michael Kim (ep 4) Heo Jae-ho as Song Jin-chul (ep 4) Yoo Soo-jeong as Oh Jin-hee (ep 4) Kwon Min-joong as Sous chef (ep 4) Choi Young-shin as Jo-eun (ep 5) Jung Jin as Manager Jung (ep 5) Ahn Sung-hoon as Jung-hoon (ep 5) Jung In-young as Kang So-ri (ep 6) Heo Jin as Kang So-ri's mother (ep 6) Jang Se-hyun as Fortuneteller (ep 6) Lee Chul-min as Loan shark boss (ep 6) Choi Ji-ho as Kang So-ri's manager (ep 6) Choi Dong-yip as Film director (ep 6) Kim Do-yeon as Hair salon employee (ep 6, 8) Byung Hun as Uhm Si-woo (ep 7) Park Sung-joon as Kim Min-woo (ep 7) Na Chang-yup as Choi Min-ho (ep 7) Park Hyo-bin as Kim Jae-hee (ep 7) Woo Jin-hee as Kwon Bo-mi (ep 7) Han Je-in as Lee Eun-joo (ep 7) Lee Jae-wook as Flasher Park Young-gil (ep 7) Kim Dong-kyun as Waxing employee (ep 7) Jung Min-sung as School security guard (ep 7) Woo Sang-jeon as Jo Joong-go (ep 8) Oh Jung-tae as Joo Tae-baek (ep 8) Kim Choo-wol as Literature expert (ep 10) Lee Sang-hong as Kim Joong-eun (ep 11) Min Ji-won as Won-bin's girlfriend (ep 12) Ratings International broadcast Philippines - TV5 - June 2015 References External links Flower Grandpa Investigation Unit official tvN website 2014 South Korean television series debuts 2014 South Korean television series endings Korean-language television shows TVN (South Korean TV channel) television dramas South Korean crime television series South Korean comedy television series