A narcotics investigator for the harbor police, Eiichi Tsuda, is driven by thoughts of vengeance for the overdose death of his brother and the subsequent decline and death of their mother. Tsuda acts viciously and with disdain for legal niceties in his exploration of the criminal facts behind the explosion of a freighter in the harbor. He goes undercover with a band of drug smugglers, but his methods threaten to destroy him as well as his case.