A simple Chinese immigrant wages a perilous war against one of the most powerful criminal organizations on the planet in this sprawling action drama directed by Derek Yee (One Night in Mongkok) and starring Jackie Chan, Daniel Wu, and Masaya Kato. In Japan, foreign migrants are shunned by mainstream society. Taunted by the yakuza, they live in constant fear of being discovered and repatriated. Into this world ventures Steelhead (Chan), a humble tractor repairman who has traveled to Tokyo in search of his missing girlfriend, Xiu Xiu (Xu Jinglei), who vanished into thin air shortly after arriving in the city. After locating his brother Joe (Daniel Wu), Steelhead discovers that Xiu Xiu has adapted a Japanese identity and married up-and-coming yakuza chief Eguchi (Masaya Kato), with whom he forms an uneasy alliance. Over time, Steelhead earns the respect of his fellow Chinese immigrants by establishing a place for them to gather. But the dark side still beckons to Steelhead, because after helping Eguchi dispense with a powerful rival, he is granted full control of Shinjuku's most popular nightspots. Resistant to the allure of the criminal lifestyle, Steelhead discovers a new love and opens a tractor-repair business just outside the city. When Eguchi begins using Steelhead's former compatriots as pawns to front the yakuza's drug trade, the vengeful immigrant returns to the city determined to exact justice, even if it means destroying the future of the woman he once loved.