Moon Joo, a seasoned diplomat and former US ambassador, has gained the trust of the international community with her intelligence and decisive actions. Uncovering the political schemes behind a high-profile murder involving both South and North Korea, she becomes entangled in a dangerous web of secrets. Meanwhile, San Ho, a skilled mercenary with a mysterious past and citizenship, operates discreetly. Though quiet, he proves to be a valuable ally to Moon Joo as they work together to uncover the truth in a treacherous world of power, deceit, and hidden plots, where exposing the truth could come at a great cost.