Ji Hyuk, an ace in the NIS Foreign Intelligence Bureau, has never failed a mission. However, during a mission by the China-North Korea borders in Liaoning, China, he goes MIA. After one year, Ji Hyuk, classified dead, suddenly appears at the Korean Consulate in Shenyang, China, in the most horrific state and doesn't remember anything that happened within the last year. With his memory lost, Ji Hyuk gets assigned to a team with minor tasks. While on the team, he meets Je Yi, who is delicate and heartwarming but with a painful past. For the first time, Ji Hyuk gets assigned to save people. As he relates to the stories of those people, he faces his memories. Will he be able to unravel all the clues and remember the past year when he went missing?