The plot revolves around two friends from the 707th Special Mission Battalion recruited into a secret South Korean black ops agency known as the National Security Service. Of the pair, recruit Kim Hyun-jun begins to uncover evidence that his foggy past may not be so irrelevant to his joining of the secret organization after all. As the two friends find their loyalties tested and forge new, unlikely alliances, the journey takes them from their home country to Hungary, Japan, and China where they find themselves at the center of an international conspiracy.
