When an invading army conquers the ancient Korean capital of Balhae, beautiful swordswoman Yeon So-ha (So-yi Yoon) sets out to help the kingdom's prince (Seo-jin Lee) return from exile and reclaim his rightful throne. But with assassins and criminals hot on their trail, only by unsheathing their lethal blades can they defeat their enemies and return the prince to power. Director Young-jun Kim's martial arts thriller also features Hyeon-jun Shin.