Kim Hyun Joon (Lee Byeong Hun) and Jin Sa Woo (Jung Joon Ho) are best friends who join NSS and fall in love with the analyst Choi Seung Hee. However, after a mission Hyun Joon is abandoned by NSS, and he swears revenge. However, his revenge leads him to the mysterious organization IRIS, whose reach is far wider and deeper than he could ever imagine. This high-profile action drama had a production cost of nearly 20 million dollars and had shoots in Japan, Hungary, and China. It is loosely based on the Korean blockbuster movie Shiri and received strong ratings throughout its run. This hit has spawned two other spinoff series: Athena ( and IRIS 2 (