Chinese laborer Steelhead (Jackie Chan) illegally arrives in Japan to search of his missing sweetheart Xiu Xiu (Xu Jing Lei), only to discover that she's married to rising Yakuza boss Eguchi (Kato Masaya). Determined to survive in Tokyo's underbelly, Steelhead unites the Chinese migrants, establishing their own community to protect themselves from the oppressive Japanese and foreign gangs. Steelhead even finds new love with bar owner Lily (Fan Bing Bing), and earns the favor of the righteous Inspector Kitano (Takenaka Naoto). However, the Chinese antagonize the entrenched Taiwanese gangsters, leading Steelhead to forge an alliance with Eguchi. As a Yakuza enforcer, Steelhead earns respect and even his own base of power. But Steelhead's Chinese brothers are corrupted by their newfound power, and an internal struggle within the Yakuza threatens their own position. All Steelhead wants is a return to simpler, honest times like he once shared with Xiu Xiu back in China. But it may now be too late.