Dietrich, who was born as the first prince of the newly emerging kingdom of Estline, lost his feelings due to his mother’s mistreatment and was called a “cold-blooded prince” by those around him. He was ridiculed. When Dietrich was thirteen years old, he met a girl. It is “Marguerite,” the daughter of the Marquise of Friedenreich and Dietrich’s fiancée. At first, Dietrich does not like Marguerite, but she is devoted to him despite her clumsiness, and Dietrich gradually forgives her. When they were both seventeen years old, the king died. In the midst of the unrest in the country, Dietrich is crowned the new king, and at the same time, he asks Marguerite to break her engagement. In this way, he wants to prevent any misfortune from befalling her. Later, Dietrich is overthrown from the throne by his brother “Oscar”. Thereupon, he was sentenced to death. When Dietrich is on the guillotine and about to die, he sees Marguerite in the crowd, praying desperately. Dietrich dies, murmuring words of apology and gratitude to her. But… When he opens his eyes again, he is somehow transported back to the day of his engagement to Marguerite. Dietrich makes a vow. “This time I will make her happy.” This is the story of a man struggling to make his fiancée happy in a world where he has returned from death and is finally called the wise king.