Frost and his men assist RSPCA officer Christine Moorhead in smashing an illegal dog fighting ring but its organizer, local gangster Gerry Berland, eludes them. One of Christine's helpers, Brian, is stabbed to death by Berland's thuggish son Sean, who believes he set the police on the ring,and Christine recognizes him and his accomplice,Neil. Berland arranges alibis for the boys and though initially appalled, his wife Sally colludes with him as he has always run her life. She persuades Neil's honest and horrified parents to go along with the lie. Having failed to warn...
Christine survives her ordeal and grows closer to Jack, who meets her apparently friendly ex-husband. To silence Lisowski,a drug addict, Berland gives him an extra strong fix,which kills him. Frost realises the two men know each other but decides to bide his time. However,he has a piece of good fortune when Salmond, Berland's cocky solicitor, has his car stole by joy-riding colleagues and Salmond's large,personal stash of cocaine is found in the car.Frost levers him into revealing the location of the site where Berland trains his fighting dogs and from here on ...