In an uneasy city where humans and vampires walk side by side, top guild slayer Scarlett eliminates bloodthirsty predators in secret. When an impending institutional audit threatens her operational standing, she enters a hasty marriage of convenience with Sebastian, an unassuming actuary with a delicate appearance. Unknown to Scarlett, her mild-mannered spouse harbors his own lethal supernatural secrets behind his quiet smile. Living under the same roof as an ostensibly ordinary married couple, both carefully conceal their true identities while attending to household chores. As danger closes in from rival guilds, maintaining their mutual facade becomes a high-stakes dance for survival.