Kim So-hyun plays Princess Pyeonggang whose mother, the Queen was killed when she was a child and whilst trying to escape she is assisted by the son of a General called On Dal played by Na In-woo. They become separated and the princess has an accident and loses her memory and she is adopted by a secret society and is trained to become a very efficient assassin. Many years later they meet by accident and this begins to unravel a chain of events going to the top of the Royal household and the events from their childhoods. It is an entertaining story and the pace of the first two thirds of the series is engaging and the momentum retains your interest. Sadly the final third is where to me the pacing is off and it would have benefitted from fewer episodes.