It was stated in many press reports that the genre of the film would be closer to drama than Chan's trademark action. Director Derek Yee said, "People are too familiar with the image of a fighting Jackie Chan. It's time for him to move on to drama." In a recent interview, Chan himself describes the film as, "maybe one per cent action. Heavy drama."

The film was originally to be released on 25 September 2008 but was delayed to the first quarter of 2009. It premiered at the 2009 Hong Kong International Film Festival and was released on 2 April 2009 in Hong Kong. In the U.S. it was released on home media on June 8, 2010.

In the early 1990s, a tractor mechanic nicknamed Steelhead (Jackie Chan) entered Japan illegally from China in search of his fiancée, Xiu-Xiu (Xu Jinglei) with the help of his "brother" Jie (Daniel Wu). Jie had shown Steelhead how to make a living by showing him trades of the underworld. One day, while illegally working as part of a clean-up crew in the sewers, Steelhead and his Chinese comrades were caught by the police. Not willing to be caught, Steelhead and others ran for their lives. Detective Kitano nearly drowned, but was saved by Steelhead; Kitano felt a life-debt to Steelhead and never pursued him.

One night, while working in a restaurant with Jie, Steelhead found Xiu-Xiu with Yakuza leader Eguchi (Masaya Kato). Saddened by seeing his fiancée with another man, he spent the night with Jie drinking and partying with hookers. Once sober, Steelhead decided to become a legal citizen of Japan by any means possible. Steelhead and his Chinese friends then went on an aggressive money laundering operation, but left Jie out of it due to his kind hearted nature. Unfortunately, Taiwanese triad leader, Gao (Jack Kao), discovered one of his pachinko machines had been tampered with (fixed by Steelhead's group) and vowed to punish the culprit. Jie was caught playing the tampered pachinko machine and was taken to a dark alleyway where Gao sliced Jie's face and cut off his right hand for information.

Upon learning Jie's fate, Steelhead sneaked and hidden inside Gao's establishment to take revenge, but instead learned of the plot to kill Eguchi between the Togawa group (rival "allies") and Gao. Gao failed to kill Eguchi; Steelhead saved Eguchi by chopping off Gao's arm with his machete and two ran for their lives. The two successfully escaped pursuit and Steelhead was welcomed to the Eguchi estate to recover.

Steelhead would have the chance to catch up with Xiu-Xiu (as an old acquaintance of the same village) as Eguchi gave them a moment to speak to each other. Steelhead learned that Eguchi and Xiu-Xiu have a little girl, Ayako. Xiu-Xiu told Steelhead her name is Yuko Eguchi now and that she was happy with her new life. Eguchi returned and offered Steelhead a high paying job, but he refused.

Later, Eguchi tried unsuccessfully to expose Togawa for the attempted assassination, but their boss made Eguchi apologize for the accusations instead. Eguchi then asked Steelhead to be a hitman. Steelhead agreed, under two conditions: he'll take control of Gao's territories and legally become a citizen of Japan. Steelhead killed all of his targets, which resulted a gang war within the Yakuza ranks; Steelhead and Eguchi got what they wanted. Eguchi was promoted after Togawa and Steelhead became a vassal under Eguchi with Gao's territories.

Steelhead did everything to make a better life for his Chinese brothers, but had no interest in the daily operations of Yakuza activity. He left all the daily operations to his brothers as he started a successful tractor business. Some time later, Detective Kitano met with Steelhead and warned him that all of his brothers have become corrupted. Kitano told Steelhead that he would be arrested along with his friends, with him charged as the head conspirator. Steelhead made a deal with Kitano: Steelhead would find evidence to have Eguchi arrested in exchange for his comrades' freedom.

That fateful night, Steelhead and Kitano returned to the vassal HQ to warn his comrades about their impending arrest if they didn't stop their operation and was met with furious opposition. His brothers violently refused to give up their rich lives they made with the Yakuza. Eguchi arrived just as Steelhead was stabbed by one of his friends. Meanwhile, the Yakuza couldn't tolerate Eguchi's leadership anymore. Gao, Nakajima (Eguchi's former subordinate), and Togawa's son agreed to take Eguchi down the same night.

Waves of Yakuza stormed into the building and proceeded to kill everyone, leaving only Eguchi, Steelhead, and Kitano to survive the onslaught. Mortally wounded, Eguchi gave Steelhead a flash drive that contained data on Yakuza operations. As Kitano and Steelhead escaped out of the building, the cops arrived and began arresting the Yakuza. Steelhead called Yuko to meet in Okobu station, along with Ayaka, but Togawa had already taken Ayako hostage and told him where Steelhead was. Nakajima intercepted Steelhead; the police arrived in time for a shootout. Kitano managed to kill Nakajima, but Steelhead suffered a bullet wound and fled into the sewers. Kitano found Steelhead being swept away by sewage currents and tried to pull him out, but Steelhead told him it was useless. Steelhead gave the flash drive to Kitano before the current swept his body away, while remembering how happy it was when he was with his comrades in simpler times.