The Promise

In a war-ravaged land where danger is rampant and food scarce, a young girl named Qingcheng feeds herself and her mother by pillaging the bodies of dead soldiers. One day, after finding some bread, Qingcheng pulls the boots off a hanging corpse for herself. However, it was all a trick as the "corpse" is not dead and he is able to string up Qingcheng. After Qingcheng promises to be his slave, he cuts her down and she asks if she can see his helmet. Upon receiving the helmet, she uses it to smack him on the head and flees.

While crossing over some water Qingcheng drops her bread, but the bread is caught by a goddess and is brought back to Qingcheng. Asked by the goddess why she does not eat the bread, Qingcheng replied that she is saving the food for her mother. The goddess then tells the girl that her mother is dead. Grief stricken, the girl eats the bread. Before she departs, the goddess offers her a chance to live a life in which she will have all the food she wants, will be able to wear the most beautiful clothing, and men will fall helplessly in love with her. However, there is a catch: all men whom she falls in love with will die. The girl readily accepts the conditions.

Years later, after a brutal battle in which his regiment of 3,000 men was able to defeat a barbarian horde of 20,000, General Guangming (played by Hiroyuki Sanada) is informed that the King is being attacked by the traitorous Duke Wuhuan (played by Nicholas Tse) from the north. While he and his slave Kunlun (played by Jang Dong-Gun), a man of supernatural strength and speed, search for the path back to the kingdom they become lost and decide to split up to find their way. However, while looking for the path, General Guangming comes across the goddess who informs him that the victory against the barbarians would be his last because soon a man wearing Guangming's crimson armor would kill the King and his name would be besmirched. Laughing, Guangming states that he would never kill the king.

After the goddess departs, Wuhuan's assassin Snow Wolf (played by Liu Ye) attacks Guangming. Kunlun finds his master wounded and his master tells him to wear his armour and save the king. Kunlun asks how can he tell who is the king and Guangming replies that the king will be the one without a weapon.

Back at the palace, the King and his princess, (the grownup) Qingcheng (played by Cecilia Cheung), stand upon the top of the palace walls which are surrounded by Wuhuan's soldiers. Wuhuan demands that the King give him Qingcheng, something the king is all too willing to do. Angered by this, Qingcheng tells the soldiers that she will strip off a layer of clothing if they will kill the king. Since her stunning beauty entrances them, they willingly attempt to do as she asks. Infuriated, the king draws his sword and it is at this point that Kunlun, dressed in Guangming's armor, arrives at the scene and throws his sword at the king, impaling and killing him, rescuing Qingcheng. However, their victory is short lived because Wuhuan and his men catch up to them. Wuhuan states that if Guangming jumps he will spare the life of Qingcheng. Kunlun, in love with Qingcheng and knowing that he can survive the fall, jumps. Kunlun returns to his master and gives back the crimson armor. Guangming is angered as he had been beaten and tied up to a tree by his own men who did not kill him only because he had been their superior officer, all because Kunlun killed the king. The two hurry to rescue Qingcheng, in which they are successful. Qingcheng is in love with Guangming because of the words he said to her before he jumped ("You must not die, you have to live"); however, she does not know that it was actually Kunlun who spoke these words, so her heart's desires are misguided. Kunlun, whose own desires come second to his master's, stands aside while Guangming tries to make Qingcheng fall in love with him.