Jongin was born in 1894. He is the Crown Prince of the Korean Empire, son of Emperor Suho. In 1916, he is 22 years-old and yet, he still doesn't want to get married, or even engaged, making his mother Lady Taeyeon, worried and suspicious as she tries her best to make her son interested in marriage. Despite the Queen's efforts, Prince Jongin, also known as Kai, still refused to marry any of the high-class ladies his mother introduced him to, being interested only in horsemanship, swordsmanship and such.

Lee Taemin, a pretty boy with long hair and feminine aura, often mistaken for a girl, is an ordinary 19 year-old citizen who works in his father's diner downtown.

Suho, of his real name Kim Junmyeon is the Korean Emperor. He loves his son, but is too busy to give him the attention and affection he needed. Thus, Jongin grew closer to his mother.

Lady Taeyeon is the Emperor's wife and Jongin's mother. She would do anything for her son's happiness, but not if it meant breaking the rules.

Oh Sehun is the Prince's companion and best friend. He had been friends with him since their childhood. Kai trusts him and relies on him on everything he does.

Kim Jonghyun and Kim Kibum are Taemin's best friends. They had been working with him for years in his father's diner.

Lee Jinki, Taemin's father, loves his son but since his wife's death, his attitude completely changed. He abandoned his diner and became addicted to alcohol, making his love for money even bigger, so he could drink more.

Choi Minho is one of the Royal Castle's high-ranking guards, in charge of the Prince's private wing.