The foreign migrant communities in Tokyo live shadowy lives. The Japanese neither acknowledge nor welcome them. They are shunned by the mainstream society, hounded by the yakuza, and go about their days under fear of being discovered and repatriated.
It is an alien world for steelhead - an honest, hardworking tractor repairman. Steelhead had decided to take the perilous journey to Tokyo after he lost contact with his girlfriend, who arrived in the city earlier.
Trying to exist in the underbelly of Tokyo long enough to find Xiu Xiu, steelhead has come to realize to migrants had to stand united if they wanted to go about their lives without fear of oppression by not only the Japanese underworld but also gangs formed by foreigner.
In his search of a decent living, Steelhead unwittingly finds himself pit against the Japanese yakuza. Ironically he also discovers that Xiu Xiu has adopted a Japanese identity and married Eguchi, an ambitious up and coming Yakuzu chief.
Steelhead wins the respect of his friends by establishing a base for them and forms an uneasy alliance with Eguchi. When he helps Eguchi dispose of a rival, he is given the control of Shinjuku's night establishments. But, uninterested in living a gangster's life, Steelhead finds a new love and takes the chance to start a tractor repair business outside Tokyo. However, his peace is short-lived when word gets to him that his former compatriots were now being used by Eguchi to front the yakuza's drug business.
Steelhead feels responsible for this turn of events and feels obligated to bring Eguchi down. He also has to hear in mind that if he goes after Eguchi, he would be destroying the newfound life of the woman he once loved. In any case, can one simple migrant take on the yakuza alone?