Sook-hee is a trained assassin who was born to kill. She was just a little girl when the training started in Yanbian, China. After the death of her mentor, when the chance of starting a new life was given to her, she came to South Korea as a government agent. They promised her that she will be free after ten years of service. So she begins her new life as a theatre actress. But soon two men Joong-sang and Hyun-soo appear in her new life. And she started to find deep dark secrets about her past. Eventually she take matters into her own hands.