The worlds of Lee Gon, the ruler of the Korean Empire, and Jung Tae-eul, a police lieutenant of the Republic of Korea, are closely intertwined with each other. It’s just that no matter what lovers do, they always break up. Traveling through time, they gradually learn the terrible truth: of two doubles, only one can exist, otherwise chaos will begin and the whole world could be destroyed... Now they are faced with the task of not only protecting each other, but also preventing the end of the world. Meanwhile, their mysterious enemy lurks in the shadows, preparing to strike a crushing blow. Will Jung Tae Eul and Lee Gon survive their unequal battle with fate and time itself? Will they find their cherished happiness? Now that almost all the secrets of the past have been revealed, only one mystery remains - who was the stranger who saved Lee Gon as a child. But the answer to this question can destroy everything...