Kim Hyun Joon and Jin Sa Woo are best friends who were brought into a top secret organization known as NSS by analyst Choi Seung Hee and Park Sang Hyun. Hyun Joon and Sa Woo both fall in love with Seung Hee when she first profiles them. Their lives are changed forever when Hyun Joon is given a solo mission in Hungary. Hyun Joon later tries to find out who set him up and to figure out what IRIS is and wants.


Cast
Lee Byung Hun as Kim Hyun Joon
Oh Eun Chan (오은찬) as Hyun Joon (child)
Kim Tae Hee as Choi Seung Hee
Jung Joon Ho as Jin Sa Woo
Kim Seung Woo as Park Chul Young
Kim So Yeon as Kim Sun Hwa
T.O.P as Vick
Hyun Jyu Ni as Yang Mi Jung (NSS staff, best Korean hacker)
Yoo Min as Sato Eriko
Kim Young Chul as Baek San (NSS vice-director)
Yoon Je Moon as Park Sang Hyun (NSS chief)
Yoon Joo Sang as Oh Hyun Kyu (NSS chief)
Lee Jung Gil as Jo Myung Ho (president)
Jung Han Yong as Jung Hyung Joon (president's male advisor)
Na Yoon as Hwang Tae Sung (NSS staff)
Kim Hye Jin as Yang Jung In (NSS staff)
Myung Ji Yun as Hong Soo Jin (president's female advisor)
Miyama Karen as Yuki
Kim Gab Soo as Yoo Jung Hoon
Park Soo Hyun as Park Joong Kwon
Jung Ho Bin as Kang Chul Hwan
Park Yong Ki as Yoo Kang Oh
Kim Hyung Jong as North Korean agent
Lee Eon Jeong
Yeo Ho Min
Lee Jung Yong
Son Jung Min
Sung Woong
Jo Ji Hwan (조지환)