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.