Agent Han Ji Hyuk gets discovered on a fishing boat. The National Intelligence Service gets notified of his identity number, but his file is locked. When they realize he's their ace agent who went missing one year ago, they rush to get him. However, Ji Hyuk doesn't remember anything that happened, leaving many questions unanswered. 

Han Ji Hyuk's memory flashes before him. He remembers that it was Choon Gil who came to the safe house in Dandong to see him. Without the agency's support, he tracks him down to find out everything that happened on that day one year ago.