Season 1

We meet Kim Seol-woo during a hostage situation, where he takes out the hostage takers against orders. He's recruited by the NIS to become a ghost agent: deeply planted into organizations, fake identities and operating discreetly.

Neither Woon-Gwang nor his chief celeb manager Cha Do-Ha likes his new bodyguard. If they can't make him leave, they'll just make him want to leave.

After leavening that Woon-Gwang has been involved in a similar accident before, Seol-Woo relays his suspicions to Lee Dong-Hyun, his comrade and mentor.

From Chairman Victor's private collection of precious cultural artefacts, a wood carving catches Seol-Woo's eye. Then the power suddenly goes out.

For his next task, Seol-woo must get close to Do-ha, but it isn't so easy when she has forbidden him to approach her within a 1-meter radius

Seol-woo gets drunk and sends cute text messages, all in the name of his mission. Meanwhile, Congressman Baek tries to make a deal with Jang Tae-ho.

To stop Seol-woo from blowing his cover, Dong-hyun tells him to stay out of the investigation. However, Seol-woo continues his search for the culprit.

Do-ha asks to hear the truth directly from Seol-woo. Meanwhile, Dong-hyun and Seol-woo begin preparation for their next mission, the Black Auction.

For the country and Do-ha's father, Un-kwang decides to help Seol-woo. Do-ha, not able to trust Seol-woo, requires him to sign a contract.

Jang Tae-ho lays down his conditions to Mo Seung-jae. For their new mission to commence, Seol-woo and Do-ha must first get the approval of Un-kwang.

Seol-woo doesn't pick up Do-ha's phone calls, so she decides to check his workroom. Dong-hyun visits Jang Tae-ho and asks if he knows where K is.

All sides involved, including Lee Dong-hyun, Mo Seung-jae and the National Intelligence Service, are continuing the search for the missing videotapes.

Jang Tae-ho and Lee Dong-hyun discuss Song Mi-eun and her past: She decided to marry Mo Seung-jae, not for his wealth but for her own survival.

The police find the vehicle involved in the hit-and-run accident. Determined to kill off the bad guys, Seol-woo gets his gun from his workroom.

For Seol-woo, it's finally time for revenge. For all involved, it's finally time for closure and for punishments to be given where they are due.

For Seol-woo, it's finally time for revenge. For all involved, it's finally time for closure and for punishments to be given where they are due.