"Marriage was never the mission. Survival is." To the rest of the world, Ahn Keonho and Y/N Ahn are an ordinary married couple living a quiet life in Seoul. Behind closed doors, however, they're hiding secrets that could destroy everything. Without the other's knowledge, both work as elite operatives for rival clandestine organizations, carrying out dangerous missions under identities known only to the underworld. By day, they're husband and wife. By night, they're ghosts. Everything changes when a routine assignment goes terribly wrong, forcing long-buried truths into the light. Suddenly hunted from every direction, the couple must decide whether to remain loyal to the organizations that shaped them-or to the marriage they never realized was built on lies. Because sometimes... The most dangerous person in the room isn't your enemy. It's the one sleeping beside you. Inspired by Mr. and Mrs. Smith.

Your ex-situationship is a famous member of CORTIS. He dumped you because he said he wasn't ready for a commitment since their K-pop group was rising in popularity, and you agreed because you're a working student. But one day, while you were on your way home, you saw Seonghyeon outside your apartment.