During the Northern Wei Dynasty, the Rouran army invaded the border, and the country called on its inhabitants to go to battle. In order to fulfill her duty for her old father, Hua Mulan disguised herself as a man and went to Changpingcang. Originally, she just wanted to perform the duty of her father. Unexpectedly, in one attempt to save the prince, her friend Yuan Hong was captured and killed in front of her. Since then, Mulan has bravely fought with the enemy and won many victories on the battlefield. When everyone was joyfully celebrating, the enemy gathered millions of rats into the city, causing heavy damage to the army. For the country's prosperity and the safety of its people, Mulan and a few soldiers protected Changpingcang to the last at the cost of their lives.