To keep her ailing father from serving in the Imperial Army, a fearless young woman disguises herself as a man and battles northern invaders in China.
In Imperial China, Hua Mulan (Yifei Liu) is an adventurous and active girl, to the disappointment of her parents Hua Zhou (Tzi Ma) and Hua Li (Rosalind Chao), who hope that one day she will be wed to a good husband. Mulan is an independent girl, who practices martial arts and can defend herself. Zhou did not have the heart to tell Mulan that only sons had the right to practice the weapon arts in China.At an early age, Mulan is a skilled girl, which she demonstrates by catching a chicken that wandered off to the roof of their community housing structure. Mulan returns the chicken to the coop and then lands safely on the ground, despite slipping from the roof. The community looks down upon Mulan as this behavior can bring dishonor and shame to the family.
As a young woman, Mulan is arranged to meet with a matchmaker (Cheng Pei-Pei) to demonstrate her fitness as a future wife. Mulan agrees as her father had always told her that her biggest mission in life was to bring honor to the family. Mulan is dressed up in the most expensive gowns and given an extensive make-up to display her potential as a bride.Mulan, flustered, attempts to pour tea in front of the matchmaker, but a spider scares the former's younger sister Xiu (Xana Tang), accidentally causing a mishap that destroys the teapot, leading the matchmaker to call her a disgrace in front of her family. The matchmaker declares that the Hua family has failed to raise a good daughter and smears dishonor on them.
To the north, an imperial outpost is invaded by Rouran warriors, under the leadership of Bori Khan (Jason Scott Lee) (a Rouran warrior-leader intent on avenging his father's death, who was killed by the Emperor in a previous attack). They are assisted by the witch Xian Lang (Gong Li), who uses her magic (Shape shifting abilities) to impersonate a trader and enters the outpost. As Bori launches his attack, Xian reverts to her original form inside the outpost and attacks the soldiers from within.
After the battle Xian poses as a surviving soldier and reports the attack to the Emperor of China (Jet Li), at the Imperial City. Due to the attack, all trade with China has been disrupted. This has the potential to end the Kingdom itself.The Emperor (Jet Li) then issues a conscription decree ordering every family to contribute one man to fight Khan's forces. The Emperor plans to deploy this new army to protect the Silk road, as that's where the attacks are concentrated.Xian works for Bori as he has promised her a kingdom where she is accepted for who she is (in Imperial China, all witches are banned). Xian was exiled from China and was wandering aimlessly on the Mongolian steppes when Bori found her and gave her an identity and a cause to fight for.
Imperial soldiers arrive in Mulan's village to enlist recruits and Zhou is forced to pledge his service as he has no sons, immediately falling over in front of the soldiers due to his bad leg. Zhou yells at Mulan when she challenges her father's decision, saying that it is his duty to bring honor on the battlefield. Realizing that her father has no chance of survival, Mulan flees with his armor, horse, and sword to join in his place.The next morning, Zhou discovers Mulan's absence, but he knows that if he exposes her, their own people will kill Mulan. Zhou prays to his ancestors and his family's guardians to protect Mulan.
Mulan wanders in the mountain for days and is lost. The family guardian, in the shape of a Phoenix, arrives in the sky to guide Mulan to her destination.Mulan arrives at the training camp, which is run by Commander Tung (Donnie Yen), an old comrade of Zhou. Sergeant Qiang (Ron Yuan) is the second in command to Tung, of the Imperial Regiment.Qiang informs the recruits that the penalty for dishonesty is expulsion and disgrace for the individual and their entire family.
Alongside dozens of other inexperienced recruits, she ultimately becomes a trained soldier under his tutelage without exposing her true identity. She bathes in the middle of the night and keeps her distance from all other recruits to protect her secret. She takes on night guard duty, so she does not have to sleep in a tent full of half-naked men.Under Tung Mulan learns to fight with a sword, shoot arrows, fighting with spears, carry 2 buckets of water up an entire mountain and so on.Mulan makes friends with fellow trainees Ling (Jimmy Wong), Yao (Chen Tang) and Chien-Po (Doua Moua). Chen Honghui (Yoson An) gets close to her, but as a guy friend. The guys wish for girls with a fair skin and who looks beautiful. But Mulan says that her ideal woman is courageous, smart and with a sense of humor.
Mulan proves to be an equal to Chen in a spear training exercise, which is also noticed by Tung. But the guys accept her as one of their own, after this event. Tung summons Mulan, and encourages her to not hide her Chi.Mulan is taught how to turn the enemy's numerical advantage into a disadvantage. Qiang says that a mere 4 ounces can move 1000 pounds with the right leverage.
The Khan's army continues to advance, forcing Tung to end training early and send his battalion to fight.The Tung army reaches the Northern Steppe garrison and receives word that Bori is moving towards the garrison, preparing for battle. Tung chooses to seize the initiative and advances towards Bori, rather than fortifying the garrison fort.
Tung's battalion meets Khan's army in the open field, but Khan himself rides away from his main attack column. Tung sends some riders after then, Mulan included. Mulan chases some troops on her own, but is confronted by Xian Lang, who mocks her for pretending to be a man. She attempts to kill Mulan, but her attacks are stopped by the leather with which Mulan's chest had been bound to hide her identity.
Mulan removes her male disguise, returning to the battle just as the Rourans begin attacking her fellow troops with a Trebuchet (Xian Lang has transformed into bats and attacked Tung's battalion forcing them into defensive clumps which were easy to target with a Trebuchet). Mulan uses discarded helmets and her archery skills to fire on the Rourans. The Rourans believe an enemy company has gotten behind them (looking at the count of helmets) and turn the Trebuchet around to fire on them.They maneuver the Trebuchet into firing on a snowy mountain triggering an avalanche that buries the Rourans.
Mulan rides back to camp and rescues Chen Honghui (Yoson An), a soldier she befriended in camp. Unable to hide her true gender any longer, she is expelled from the army and begins her return home.
On her way, she is confronted by Xian Lang, who reveals that she was also shunned by her people (who were afraid of her powers as she grew more and more powerful) and fights for Bori Khan only because he treats her as an equal and that no one else does. Additionally, she reveals that the attacks on the outposts have been a diversion, as Khan's true plan is to capture and execute the Emperor for having his father killed. Risking execution, Mulan returns to her battalion to warn them of the impending capture. The soldiers she befriended stand up for her (Cheng says that she risked her life and is the bravest soldier in the battalion), and Tung decides to believe her, and allows her to lead a unit to the Emperor's palace.
Xian Lang uses her magic to be in the image of the Imperial Chancellor (Nelson Lee) and persuades the Emperor to accept Bori Khan's challenge to single combat, while removing the city guards from their posts. The guards are murdered, and the Rourans prepare to burn the Emperor alive.
Mulan's unit distracts the Rourans while Mulan's path is cleared to reach the Emperor. Khan tries to snipe her with an arrow, but Xian Lang, sympathetic to Mulan (Xian realizes that Mulan has been accepted by society as a woman as she was leading Tung's unit sent to protect the Emperor, but Xian was simply exploited by Khan) and disenchanted from Khan, transforms into an eagle and sacrifices herself by intercepting the arrow.Mulan kills Khan, but not before he disarms her and destroys her father's sword. She frees the Emperor, who offers to let her join his personal guard. She declines the offer and returns to her village.
Mulan is reunited with her family. An emissary from the Emperor, under the leadership of Commander Tung, arrives to present Mulan with a new sword, while making a personal request that she join the Imperial Army as an officer.
