China, 9th century. As the province of Weibo attempts to break free from imperial authority, Nie Yinniang returns to her family after many years in exile. Her upbringing was entrusted to a nun who, in the utmost secrecy, trained her in the martial arts. Now a vigilante, her mission is to kill Tian Ji'an, her cousin, former lover, and the new governor of Weibo. Nie Yinniang will have to choose: sacrifice the man she loves or break away from the ‘Order of Assassins’ forever.