During the Qin dynasty, the general Meng Yi, Jackie Chan, is tasked with escorting the Korean princess Ok-Soo, Kim Hee-seon, back to China to become the Qin emperor's concubine. Along the way, Meng Yi is wounded while protecting Ok-Soo, and the two develop a deep, emotional bond that challenges their duties yet never breaks the loyalty owed to their roles. As they travel through hostile lands and navigate dangerous political entanglements, their connection grows more real, even as they remain dedicated to their respective responsibilities and the fate that history has laid out for them.
When the Qin emperor falls gravely ill, he sends Meng Yi on a perilous quest to obtain the elixir of life—the only thing that might save him. Before departing, Meng Yi openly confesses his love for Ok-Soo, and she vows to await his return. On the ambush-filled journey, Meng Yi entrusts the elixir to his deputy, Nangong Yan, Shao Bing, before he succumbs to his wounds. Nangong Yan succeeds in delivering the elixir to the emperor, but the prince and the chancellor force Nangong Yan and Ok-Soo to test its authenticity by drinking it. The two achieve immortality, yet their triumph condemns them to imprisonment within the Qin emperor's mausoleum for eternity.
In the present day, Meng Yi has been reborn as Jack, an archaeologist who often dreams of his past life. He, along with his friend Tony Leung Ka Fai, travels to the floating tomb of a Dasar prince in India to locate a rare material capable of creating a zero-gravity field. When William accidentally causes the tomb to collapse, Jack falls into the river and is saved by Samantha, Mallika Sherawat, who takes him to meet her uncle, a Kalaripayattu guru. While dueling with one of the guru’s students, Jack experiences a vivid vision of Meng Yi duelling the Dasar prince, gaining a new understanding of his mesmerizing past life. He and William eventually return home and donate the sword to the National Museum of China. Their bold actions anger Professor Koo, Sun Zhou, the leader of the syndicate funding their treasure hunt.
After extensive research, they conclude that the material creating the zero-gravity field is a fragment of a meteorite that fell to Earth during the Qin dynasty. They determine the mausoleum of the Qin emperor lies behind a waterfall, and the tomb—now a massive, gravity-defying chamber—appears as a floating palace powered by that meteorite fragment. Inside, Jack encounters Ok-Soo and Nangong Yan, who mistake him for Meng Yi. Professor Koo and his men soon enter and attempt to seize the elixir, triggering an aerial confrontation. William’s careless move disrupts the balance of the field, causing the tomb to collapse; he drowns in mercury as Jack fights to escape. As the structure buckles, Ok-Soo declines to join him once realizing he is not the man she once knew as Meng Yi. Nangong Yan seizes Koo, and the two fall to their deaths.
Back at home, Jack reveals a published copy of The Myth—a book he wrote about his extraordinary adventures—and dedicates it to his late friend, William.
