Archeologist Jack keeps having reoccurring dreams of a past life, where he is the great general Meng Yi, who is sworn to protect a princess named Ok-Soo. Jack decides to go investigate everything with his friend William.
Martial arts legend Jackie Chan stars as Jack, a world-renowned archaeologist who has begun having mysterious dreams of a past life as a warrior in ancient China. When a fellow scientist enlists his help locating the mausoleum of China's first emperor, the past collides violently with the present as Jack discovers his amazing visions are based in fact. Assisted by the spirit of a noble princess...—Anonymous
During the Qin Dynasty, general Meng Yi (Jackie Chan) is tasked to escort Princess Ok-Soo (Kim Hee-Sun) from Korea to marry the Qin emperor in China. Along the journey, a Korean warrior (who is betrothed to the Princess) attempts to seize her back, but Meng Yi saves her.The Korean Warrior is a general and says that the marriage of Ok-Soo to Qin is a surrender of Korean sovereignty. Since Ok-Soo refuses to go back with the warrior, he attempts to kill her. Meng Yi prevents Ok-Soo's carriage from falling into a mountain ravine by putting his own body on the line. As the Korean warrior attacks Meng Yi, Meng Yi accidentally kills him and saves the princess.
Along the way, Meng Yi is injured (when he and Ok-Soo are attacked by bandits and one of them manages to stab Meng Yi with his sword) while protecting Ok-Soo. Ok-Soo stitches his wound with a strand of her own hair. During a biting cold wave, Meng Yi is almost frozen to death as he stands outside the cave while Ok-Soo sleeps inside. Ok-Soo drags a frozen Meng Yi inside and shares her body heat with him to revive him.They develop romantic feelings for each other, but Meng keeps his honor by rejecting her and successfully completing his mission.
The Qin emperor becomes critically ill later, and he sends Meng Yi to find the elixir of immortality, the only thing that can save his life. Before leaving, Meng Yi confesses his love for Ok-Soo, and she vows to await his return.The guards escorting the elixir are ambushed by rebels on the orders of the treacherous prince and chancellor.
Meng Yi hands over the elixir to his deputy Nangong Yan (Shao Bing) and dies in the ensuing battle. Although Nangong Yan manages to bring the elixir to the emperor, the prince and chancellor accuse him and Ok-Soo of treason. The prince and the chancellor force Nangong Yan and Ok-Soo to test the elixir's authenticity by consuming it. They become immortal but are condemned to imprisonment in the Qin emperor's mausoleum for eternity.
In the present-day in Feb 2025, Jack is an archaeologist, and is the reincarnation of Meng Yi, as he often dreams about his past life. Jack records all his dreams in a journal that he maintains.One day, his friend William (Tony Leung Ka-Fai) is recruited by Maggie (Maggie Lau) for her anti-gravity project. Maggie works for a person, who is the sponsor of the whole project.William invites Jack on a quest to find a rare material that can create a field of zero gravity.
They travel to a floating tomb of a Dassar king in India (the tomb is over 2000 years old. It was said that the King became immortal after his death and then his tomb started floating), where Jack finds a sword beside the floating coffin and has a recollection of a duel he had with the king in his past life.
The inscription on the coffin revealed that the Dassar King traveled to Qin with many gifts and women. Qin offered him one of his concubines in return, but Dassar King chose his favorite. The King reneged and gave him her portrait instead. As a result, the Dassar King fought a battle with Qin's trusted warrior and exchanged a sword with him. The coffin had the portrait inside, and Jack realizes that it belongs to Ok-Soo.
William removes a piece of the material and accidentally collapses the zero-gravity field holding up the tomb, thereby destroying it. William manages to escape but Jack leaps off a cliff and falls into a river. He loses consciousness and drifts along with the current until he is saved by an Indian girl named Samantha (Mallika Sherawat). Later, Samantha brings Jack to see her uncle, a Kalaripayattu guru (Ram Gopal Bajaj) (a master of the 275th generation), who enlightens him about his past and future.
Jack succeeds in returning home safely after escaping the protectors of the Dassar King's tomb, and he delivers the sword to the National Museum of China as a national treasure. His action angered the leader Professor Koo of the secret organization that has been funding Jack and William's treasure hunt.William had delivered the stone to Maggie (without telling Jack), who determined that the stone is not from any material on Earth and that if the light from the stone is blocked, it also blocks its anti-gravity properties.
Jack says that the sword belongs to all humanity, whereas William argues that even his experiments can benefit the whole of humanity. The sword could be a clue to unlocking the secrets of anti-gravity and that Jack should have allowed him to study it before giving it to the museum.William finds that his sponsor is Professor Koo, a known grave robber and is livid. Koo counters that even William robbed the grave of the Dassar King and order him to stay with Jack.
After extensive research, Jack and William conclude that the anti-gravity material is actually fragments of a meteorite that fell to Earth during the Qin Dynasty. They find the exact location of the Qin emperor's mausoleum, concealed behind a waterfall.
The massive tomb contains the strongest fragment of the meteorite, which is powerful enough to make the tomb become a floating palace. Jack meets Ok-Soo and Nangong Yan inside the tomb and they mistake him for Meng Yi. Just then, a group of intruders led by the secret organization's leader enters the tomb and they attempt to seize the immortality elixir, leading to an aerial fight between both of them.William accidentally breaks the balance of the field after removing a piece of the meteorite and causes the tomb to collapse on itself and dies after drowning in the mercury river.
Jack escapes from the collapsing tomb, asking Ok-Soo to come with him, but she refuses after realizing that Jack is not Meng Yi, saying that she will wait for real Meng Yi forever because she believes that he exists.
Jack writes a book about his experiences, which he dedicates to William.
