At the young age of 11, Lee San witnesses his father Crown Prince Sado's death, but he does not lose his cheerfulness with his strong heart and a gentle personality. He even inherits his grandfather's intelligence, King Yeongjo, and a warm view toward humans. Lee San, who is good at both studying and martial arts, becomes the next king after Yeongjo. Song Yeon is the woman King Jeongjo loves. Song Yeon is talented in painting thanks to her father from a flower garden. While running errands in the royal art department, she enters the palace and establishes a relationship with Lee San. Will Lee San be able to overcome various schemes, stand up against maligning forces, and ascend as a king? And will he be able to achieve love with Song Yeon despite their difference in status?