et during the early Joseon Dynasty, the film begins with the queen mother and former concubine (Park Ji-young) in a precarious position of having no blood ties to the childless king (Jung Chan). She schemes to replace him on the throne with his stepbrother and her submissive young son Seong-won (Kim Dong-wook). Indifferent to his mother’s plans, the timid prince falls in love at first sight with Hwa-yeon (Jo Yeo-jeong), an aristocrat’s daughter, who has already found love with Kwon-yoo (Kim Min-joon), a commoner. The king is eventually poisoned to death by the queen mother, who is desperate to be in power. Hwa-yeon is moved to a closely watched humble residence, with the queen mother planning to assassinate Hwa-yeon and her son to secure her position in the palace.

Overview from themoviedb.org