Choi Soobin, the crown prince of the Choi family, is a rare gentleman in the turbulent officialdom. He comes from a noble family, has a good grasp of both literature and martial arts, and has a face like the full moon, and an extraordinary demeanor. He is especially trusted by the Emperor to hold an important position in the court. Since taking office, Soobin has always taken "taking the people as the root" as his motto, being fair and honest, never letting a single selfish thought get in the way of politics.

Although he is still young, the crown prince's spirit and virtue have made many old ministers admire him, and the people of all provinces and districts praise him as "the most pure lotus flower" in the capital. Soobin's temperament is not that of a trivial flower, but is calm and profound, like a green pine on a snowy mountain top, steadfast against all the storms. Every time he personally went down to the common people to inspect the fields and listen to the people's hearts, the common people would kneel down and thank him, tears streaming down their faces as if they had met a saint.

With a handsome appearance that made others not dare to look straight at him, coupled with a dignified demeanor, he soon became the dream of countless young ladies throughout the capital. Many prestigious families competed to entrust their beloved daughters to him, sending letters of marriage, the Choi family mansion never had a day without flower palanquins, dowry, invitations... However, Soobin still wholeheartedly refused.

He was cold towards love affairs, and even more disdainful of the custom of taking concubines and collecting concubines. Once, in front of the courtiers, Soobin resolutely and boldly told the Emperor:

"I vow to serve the country with all my heart, not asking for concubines or concubines, only wishing for a pure heart, free from the dust of the world."

Since then, people have praised him as the white moonlight in the royal court, a man of two wonders – both loyal and upright, and noble beyond the world. But behind that calm appearance, no one knew that in Soobin's heart there was a vague crack, a closed memory from his youth – a look, an oath, a person that could not be reached...