After the fall of Sanggyeong, the capital of Balhae in 926, Khitan establishes Dongdan Kingdom meaning Eastern Khitan. Dongdan Kingdom dispatches Chucksaldan, a group of the hit squads and sweeps out the royal family in order to prevent a reconstruction of Palhae. Resistants who are composed of the rest of the followers of Palhae leave to find out the family member of the king, who is able to rebuild Balhae.

The movie begins at the quarters of Balhae Crown Prince Dae Soo-Hyun. An eagle passes by and screeches. Soohyun hears this and knows that the Chuk Sal dan is about to hit. His Imperial guards see the walls fly, and two arrows kill of several soldiers. A battle ensues as the Balhae Imperial guard and the CSD fight off. Gun appears and sees that Mae and the CSD soldiers took care of the Imperial guard. Gun and Mae enter the Crown Prince’s quarters. Suddenly, the captain of the Imperial guard enters the room to protect the Crown Prince, but is killed by Mae. Gun asks the Crown Prince and gives him one more chance to surrender to the Dongdan, but the Crown Prince refuses. He unsheathes his ‘Mooyonggum’ (shadowless sword), and charges at Gun, but Gun gets the Crown Prince from below, and the scene ends with rain and thunder. Then, the Crown Prince is shown lying down on a bloody floor with his sword out of his hand. The results of the duel are clearly shown… (Wikipedia)