Based on the book by Bernard O'Mahoney, events kick off as convict Darren Nicholls (Adam Deacon) falls in with prison kingpin Mickey Steel (Regan).
Together they make a pact with psychotically violent inmate Pat Tate (Hassan) to flood British clubs with drugs smuggled from Europe.
Meeting tough guy Tony Tucker (Stone) and his dealer pal Craig Rolfe (Maskell) on the outside, Tate forms an alliance with the men to distribute Steel's merchandise.
Despite the financial success of their operation, the gang's brutal, unhinged behaviour brings them into conflict with the low-key Steel, who exacerbates matters by having an affair with Kate (Kierston Wareing), Tate's abused wife.
As Tate, Tucker and Rolfe scheme to remove Steel from the equation, the wily drug importer has some deadly plans of his own.