King the Land follows the story of Gu Won, the sophisticated and cold-hearted heir to the King Group, a luxury conglomerate that owns hotels, airlines, and distribution companies. Having been thrust into a cutthroat inheritance battle, Gu Won returns to the King Hotel to find the truth about his mother's disappearance, despite his disdain for insincere smiles and corporate politics. At the hotel, he crosses paths with Cheon Sa-rang, a cheerful and dedicated employee known as the 'Smile Queen' for her ability to maintain a bright demeanor regardless of the circumstances. As their paths collide, the stark contrast between Gu Won's cynicism and Sa-rang's optimism leads to a series of misunderstandings that eventually blossom into a genuine, heartwarming romance as they navigate both professional challenges and personal growth.