For a century, the Demoniacal Kingdom and the Promised Dynasty have held a fragile peace after a devastating war between good and evil. But as the Demoniacal Kingdom teeters on the brink, weakened by the scars of battle, a new alliance is proposed to strengthen their bonds: a royal marriage. To the King and Queen of the Promised Dynasty, this union is a welcome relief. But for Prince Wonwoo-the proud lion prince of the Promised Dynasty-learning that he is to wed Princess Okome, daughter of King Titanosaurus of the Demoniacal Kingdom, is anything but welcome news. Reluctantly, he agrees, bound by duty to his kingdom. Yet, just as hope begins to emerge, a single fateful mistake by Prince Wonwoo plunges both kingdoms into a violent conflict, igniting a resentment that may never be extinguished. As the smoke of war rises, it marks only the beginning of the end.