In the not-too-distant future, efforts are underway to reunite the Korean peninsula. To facilitate this monumental task, the South Korean government, in dire need of substantial financial resources, invents a groundbreaking technology known as the TWR, a high-speed nuclear reactor. This innovation attracts the attention of other nations eager to acquire it. To avert potential threats following the TWR’s development, the government forms a new entity called the National Anti-Terror Service (NTS). Jung-Woo, portrayed by Jung Woo-Sung, is reassigned from the NIS to the NTS. Initially thrilled by the prospect of becoming a true agent, he soon realizes that his primary duty involves monitoring North Korean defectors.