Sun Hyang is a special agent working for the Korean intelligence services. One day, she stumbles upon Baekhyun, the witness to a scene he was never supposed to be involved in. Sun Hyang doesn't have a choice: to complete her mission successfully and protect Baekhyun, she'll have no other option but to put up with this new teammate of sorts - who makes the young soldier lose all self-control, and whom she seems unable to contain. From arms trafficking to street shootings, or from double agents to Baekhyun, the real menace to Sun Hyang's survival may not be what it seems...