This interpretation tells of Gwang Hae (Cha Seung Won) as the son of a concubine and secondary heir, who in his thirst for power, usurps the Crown and ousts his half-sister Jung Myung (Lee Yun Hee) from the palace. Gwang Hae is then deposed in a coup by the Westerners, who replace him with In Jo (Kim Jae Won). Extremely paranoid and wanting to stabilize his position, he is also out for Jung Myung's life.
(Source: DramaWiki)