A gang of criminals, led by sociopath Max Brant, escape from France and set up a counterfeit operation to make British £5 and American $20 notes in the cellar of a large English country house now owned by Louie Bernard. Brant forces Bernard, who worked for the British Government during WW2 making foreign counterfeit currency, to make the master die plates by holding his daughter, Carole an artist, as a hostage. When Bernard finds out that Brant has tried to rape his daughter and has killed his housekeeper, Gerta, because she witnessed the attempted rape, he anonymously posts one of the forged £5 notes to the police with a letter describing the counterfeit operation. When Brant is told about this by Duke, he confronts Bernard. Meanwhile, the police slowly close in on the gang's headquarters.
The film features professional snooker world champion Horace Lindrum in a cameo appearance playing himself. This is used as cover for one of the meetings with other criminals to discuss the sale of the forged British £5 notes to them. Another similar meeting is camouflaged as a boxing match.
