Set in the Han Dynasty, a young girl, Anni, runs away from the palace after her family is executed. She swears to never be involved with the palace as she comes into the care of a coldhearted assasin, Do Kyungsoo, feisty gambler Chen, and expert swordsman Kai. When a chance encounter goes wrong, her 'parents' swear to protect her and join the palace. Anni vows to be reunited with her family and enters the palace as she unravels the secrets behind her upbringing and masquerades herself in a forbidden love that she hopes is only an assignment. What will happen to her fate and of those entertwined with her?