Two orphans named Yao Lung and May Yip grow up together in Russia with their adoptive family, and over the years their friendship blossoms into a deep romantic love. They make a solemn promise to remain together forever. One day, Yao Lung witnesses a brutal murder carried out by a shadowy assassin. Soon after, he is captured by a secretive and powerful cult of assassins known as the 800 Dragons. The cult strips Yao Lung of all his past memories through brainwashing and subjects him to intense, brutal martial arts training, molding him into the perfect killer. He becomes the assassin known as Freeman.

Years later, during an assassination mission in Hong Kong targeting a Yakuza leader, Freeman is spotted by May Yip, who has never stopped searching for her lost love. She recognizes him despite his mask. The 800 Dragons enforce an unbreakable code: any witness who sees an assassin during a mission must be eliminated. As May speaks to him about their shared history, fragments of his erased past begin to resurface. Torn between his programming and the lingering emotions for May, Yao Lung chooses to follow his heart and disobeys the cult by refusing to kill her. This act of defiance makes them both targets. With the full force of the 800 Dragons now hunting them, Yao Lung and May Yip are forced to go on the run, fighting for their survival against the very organization that created him.