Today marks the 145th day from when a man ignited the fire within a new recruit’s heart. That man is none other than ‘Gi Joo-won’, the extraordinary ace of NSO, a secret investigation agency affiliated with the government. Although known to have a bad personality among his coworkers, she still finds him attractive, especially when he frowns. Just then, a golden opportunity came upon her. As if it wasn’t enough that they became a fake couple, she even ended up living together with him! Where would this act with hidden motives possibly lead to?