In AD 450, China's ruling North Wei dynasty was under constant threat from the Rouran tribes. The Chinese military conducts a nationwide parade. A retired soldier named Hua Hu insists on enlistment once more to serve his country. Hua Mulan (Zhao Wei), his young daughter, is quite intelligent and is proficient in many types of martial arts. But because she is a girl, she cannot enlist. At night, Mulan takes her father's armor and weapons, disguises herself as a man, and runs away from home with the family horse. Joining the Wei army on behalf of her father, she was recognized by her friend Fei Xiaohu "Tiger" (Jaycee Chan) and agreed to keep her a secret.
Mulan befriends Wentai (Chen Kun), the battalion commander, as well as the other recruits "Scholar" and "Fatso" and his younger brother. During her harsh military training, Mulan proved to be brave and ready to fight, protecting others from bullying by his army commander nephew, "Turtle".
One night, while Mulan is bathing in a secluded hot spring, Wentai unexpectedly meets Mulan. After a brief fight, Mulan escaped without being identified. However, Wentai is determined to discover the woman hiding in the camp. Worse still, during the training, the Turtle accidentally dropped a valuable jade pendant, kicked by Tiger into a nearby lake as an act of revenge. Convicted of stealing battalion, the military commander ordered a raid. Tiger is unable to find the jade pendant in the lake and Mulan, fearful of revealing herself as a woman and tarnishing her father's reputation, admits to having committed the theft.
In prison awaiting her execution, she told Wentai the fact that she was a woman and asked him to keep her death a secret from her father. Wentai agrees and says he will burn her body personally so no one will know her secret. However, the Rourans launched a surprise attack on the camp, and in the confusion, the Wentai released Mulan from prison. Mulan, however, stays behind to fight and eventually kills Rouran's attack commander. As a result, she was pardoned and promoted to commander in chief. A funeral was held for the army commander, who died in the attack, and after losing his uncle, the Tortoise no longer bullied and befriended other soldiers.
Achieving even more feats during the war, both Wentai and Mulan eventually became shoguns, however, Mulan had to witness the deaths of her comrades including Fatso and his brother. During one excursion, Wentai and his men were ambushed and the Wentai ordered Mulan to stay guarding the army's supply train as he strengthened the front. Afraid of Wentai, Mulan delegated Scholar and followed him. Scholar and his men are ambushed one by one, and Mulan is devastated by the death she caused. Wentai reminds her not to invest her emotions on the battlefield. When she asked if he would do the same to her, Wentai said, "I won't." When Mulan wants to leave the army and no longer serve as a general, the Wentai reminds her that none of them want to fight and that she must do her duty regardless.
Leaving Mulan indifferent to stay at the camp, Wentai leaves for another battle. Tiger returns to inform Mulan that Wentai is dead and that his last words are to keep her strong. Mulan is devastated and has to go drinking. However, with Tiger's help, she returned to her military life and achieved many successive feats. It is revealed that Wentai is, in fact, alive; He and Tiger are keeping this a secret so that Mulan can keep his feelings free and strong.
Unfortunate that the Rouran tribes were discussing an end to their attacks due to heavy casualties, Prince Mendu killed his father and succeeded him as chief, shortly after his sister As the princess of all rourans suggested to her father Danyu that she should become queen wei and the 150-year-old rourans for peace and trade between north and south, her father confesses she must be a girl. younger, therefore not of Danyu lineage. Prince Mendu silenced disagreements in the Rourans and unleashed a massive strike force on Wei, with the intention of finally acquiring the metal-rich lands that the Rourans had been lacking for generations.
Mulan proposed a strategy to the Wei army commanders that her army would initially engage the Rourans at a predetermined location, allowing a larger puppet force to ambush the Wei from behind. Mulan's army fought vigorously against the Rourans, but many people, including Mulan, were wounded in a series of arrow bullets. Suddenly, a giant dust storm called Poison Dragon appeared, and everyone on the battlefield was consumed by it. When they regained consciousness, Mulan was reunited with the Wentai and, upon seeing Rouran's reserves enter the battlefield, they ordered a retreat into the closed gorge. The wounded Wei soldiers, including Tiger, were left in a hasty retreat. Knowing that Mulan was trapped in the canyon, Mendu stopped his army at the entrance. The supply was said to have been delivered first but went missing, and thus Mulan's forces rapidly weakened over the next few days. Mulan is seriously ill but is kept alive by the Wentai, who gave her her own blood when the water supplies ran out.
The Rourans attacked Hoa Moc Lan's army, executed the wounded Wei, including the Tiger, that were left in the retreat. Turtle was killed in an emotional attempt to stop the executions. When Mulan realizes that Commander-in-Chief Wei is not bringing troops and has betrayed Mulan out of jealousy with her skills, she prepares her impoverished soldiers for a final battle to the death. . However, Wentai went to the front lines and declared himself the Seventh Prince of the puppet state; He offers to be taken prisoner to give Mulan and her soldiers freedom. Mendu made him a prisoner and provided supplies and medicine to Mulan and her army.
Ordering her soldiers to return home without her, Mulan disguised as a Rouran woman and infiltrates Mendu's camp to save Wentai. Meeting secretly with Princess Rouran, she reveals her gender as a woman and the two share their dreams to prevent war and have peace. Mendu announced that the Wei emperor had agreed to the Wentai ransom and the noisy celebrations began throughout the camp. Tied in Mendu's tent, Mulan assassinates Mendu with the help of Princess Rouran and her middle servant.
Zhao Wei as Hua Mulan Xu Jiao as the young Hua Mulan Chen Kun as Wentai Hu Jun as Mendu Jaycee Chan as Fei Xiaohu Nicky Lee as Hu Kui Liu Yuxin as Princess Rouran
Yu Rongguang as Hua Hu Vitas as Gude Sun Zhou as emperor of the Wei Dynasty