Chul-soo is one of Korea’s best intelligence agents: he can accomplish any given mission. One day, a mysterious explosion takes place in Seoul. Chul-soo flies to Thailand on a mission to rescue a person who holds clues to the incident. Meanwhile, Young-hee goes on a business trip to Thailand and gets entangled with Chul-soo’s mission. Will he accomplish his mission and save his wife at the same time?

1930s Korea, in the period of Japanese occupation, a new girl, Sook-hee, is hired as a handmaiden to a Japanese heiress, Hideko, who lives a secluded life on a large countryside estate with her domineering Uncle Kouzuki. But the maid has a secret. She is a pickpocket recruited by a swindler posing as a Japanese Count to help him seduce the Lady to steal her fortune.

Ji-hoon became a wanted man because of betrayal by one of his colleagues. To avoid being arrested by police, he sneaks into a stranger’s house one day. However, what was happening in the house was that wife walks in on her husband having an affair with another woman? Under the absurd situation, Ji-hoo captures them all as his hostage. The hostage captor has become a welcome guest for the wife, Eun-joo. Eun-joo has dropped by her house to take a short break while holding a funeral. However, she finds two unwelcome guests in the house. One is her friend, who is having an affair with the husband. The other one is the hostage captor, a stranger, whom Eun-joo has never seen before. Nonetheless, the hostage captor is on Eun-joo’s side now, who has no one to lean on.

In 1933, when Korea was under Japanese occupation, five people in Gyeongseong are suspected to be "Phantom" spies of the anti-Japanese organization.