A disgraced heir from an elite family hides his identity while working at a rival conglomerate. Branded as incompetent, he is chosen as a fake fiancé by the company's ice-cold CEO to deflect her family’s pressure. Unbeknownst to all, he is a legendary figure—a shadow monarch of the underworld, a mercenary king, and a revered healer. At a patriarch’s birthday celebration, his modest gift is mocked until a revered antiquities expert reveals it as a priceless national treasure. He exposes the fraudulence of other heirs’ lavish offerings, humiliating the scheming family. Meanwhile, his own father arrives with an arranged bride, tightening the web of deception. When the family obsesses over securing invitations to an exclusive state banquet honoring the mysterious "Dragon King," he casually claims he can obtain ten passes. Skepticism turns to shock when a high-ranking envoy delivers them personally, confirming his unimaginable power. As alliances shift and secrets unravel, his true identity threatens to overturn every lie—and rewrite the rules of the game.