According to Korean folklore, the Ja Myung Go is a mystical drum that beats whenever an enemy state is approaching. Based on that famous story, this drama retells that story with a twist: the Ja Myung Go isn't a drum, but a princess. Born to the king of Nangnang, Ja Myung Go and her half-sister La Hee find themselves caught up by an oracle that foretells one sister as the bringer of destruction and the other a savior. La Hee's mother uses her powerful background to convince the king that her daughter is the savior. Ja Myung Go's mother barely manages to save her, and the forgotten princess is raised outside the palace. In a twist of fate, both sisters fall for the same man, the prince of the enemy state Goguryeo, and battle for their rightful place in the palace. A mix of fantasy and historical genres, Ja Myung Go features two rising stars: Park Min Young of Sungkyunkwan Scandal and Jung Ryeo Won of My Lovely Sam Soon.