The heroine Balsa is a skilled bodyguard and a masterful spear-wielder. One day she rescues Prince Chagum who has fallen into a river. The prince is carrying a mysterious spirit egg in his body, and is in danger of being assassinated by his father, the Mikado, who fears this will damage his imperial prestige. Balsa embarks upon a perilous journey when she accepts the queen’s plead to protect her son from her husband.