Du Qiu is a Chinese attorney employed by Osaka-based Tenjin Pharmaceuticals, having successfully defended the company against numerous high-profile lawsuits. About to be relocated to the United States by his management, Qiu attends a party where Tenjin President Yoshihiro Sakai appoints his son, Hiroshi, as the new head of research-and-development. Qiu briefly meets a half-Chinese woman, Mayumi, but loses track of her. Sakai tells a mysterious woman to seduce Qiu into remaining in Japan. She dances with him at the party then sneaks to his house before he arrives later. Qiu awakens to find the woman dead in his bed. He calls the police and pleads his innocence, but is nonetheless taken into custody. The arresting officer, Yuji Asano, suddenly knocks out another officer and tells Qiu to run. Qiu loses pursuing police by fleeing to a subway station under-construction. Veteran detective Satoshi Yamura is called in with his rookie partner Rika to track down Qiu, much to Asano's chagrin. Following his intuition, Yamura and Rika travel to the construction site where they find Qiu disguised as an employee. Qiu holds Rika hostage with a
nail gun, but Yamura surrenders himself and his gun to save Rika. Qiu takes Yamura hostage and claims he is innocent but the two end up in a fistfight, Yamura eventually gets the upper hand but Qiu overpowers Yamura after he is distracted by white pigeons. Qiu manages to escape apprehension and seeks shelter in a nearby shanty town, where he's befriended by the Mandarin-literate local Sakaguchi. Seeking answers, Qiu contacts Sakai and demands a face-to-face meeting, suspecting that his former employers have set him up. Sakai secretly hires a pair of assassins, Rain and Dawn, to kill Qiu, and sends one of his lawyers to the arranged meeting spot. He explains to Qiu that Sakai and Hiroshi have been secretly developing projects for military contractors. Aiming at Qiu with a sniper rifle, Rain is unable to carry through with the hit because Qiu had earlier shown her kindness, shooting and killing the lawyer instead. Yamura pursues Qiu in a high-speed
jet ski chase and nearly catches him, but Qiu is suddenly intercepted by Mayumi, who helps him escape on a
Shinkansen. Fleeing to her remote farmhouse, Mayumi explains that her fiancé, a scientist employed by Tenjin, was falsely accused by the company of stealing their classified formula, and subsequently committed suicide on their wedding day after losing the lawsuit led by Qiu. Qiu apologizes, insisting that the information he was given in regards to the case came directly from the authorities. The two are suddenly ambushed by Rain and Dawn on motorcycles, but Yamura arrives and fends them off while they flee. Yamura pursues Qiu and saves him and Mayumi after their car wrecks before handcuffing himself to Qiu, insisting on taking him in. Mayumi tells Yamura that she was with Qiu at the time of the murder, proving his innocence. The trio hole up at the farmhouse, where they manage to fend off an assault by an army of hitmen, but not before Yamura is shot. Dawn is severely injured and injects herself with a stimulant to recover, but overdoses and dies in Rain's arms. Rika subsequently drives Yamura and Qiu to a hospital, and they let Qiu go. Blackmailed over his drug addiction, Asano reveals himself to be working for Sakai and demands he be compensated for his part in framing Qiu to divert attention from the real murderer, Hiroshi. Sakai swiftly has Asano killed by Rain. Meanwhile, Rika runs an analysis on Asano's drugs, and finds they match the formula Mayumi's fiancé had been working on. Mayumi gives Rika a secret equation necessary for decoding the formula to properly reproduce the drug, a powerful stimulant, before she is captured by Rain. Sakaguchi helps Qiu sneak onto a truck carrying Tenjin test subjects, but once at the laboratory he is separated from the others and subjected to an excruciating treatment that causes him to become an involuntarily violent, nigh-invulnerable killer. Sakaguchi tries to kill the other prisoners, but has a moment of clarity and commits suicide. Sakai recognizes Qiu among the subjects and order he be subjected to the treatment, designed to turn a person into a near-superhuman, brainwashed soldier. Yamura arrives and offers Sakai the decoding equation in exchange for Qiu. Rain, realizing that Sakai is ultimately responsible for Dawn's death, releases Mayumi and gives her a gun. Qiu is injected and forced to fight Yamura, but he manages to break his conditioning and the two turn on the guards with the help of Rain. Qiu, Yamura, Mayumi and Rain end up fighting through hordes of guards through intense firefights. Hiroshi injects himself with the updated formula, surviving several gunshot wounds before finally succumbing and dying, confessing to the murder Qiu was accused of. Sakai shoots Rain, and wounds Qiu but is cornered by Qiu and Yamura, begrieved by his son's death, Sakai commits suicide. Rain dies in Qiu's arms, and Rika arrives with police backup. Weeks later, Qiu meets Yamura at a train station, where they shake hands and exchange names in Japanese and Mandarin, respectively. Yamura bids Qiu farewell as he boards the train with Mayumi, before walking off with Rika. ==Cast==