In between gigs writing two of the first films from director John Boorman and the sequel to The French Connection (1971), writer Alexander Jacobs adapted this bloody, violent drama from a pulp crime novel. Oliver Reed stars as Harry Lomart, a dangerous convict who's been planning a breakout with a fellow inmate, Birdy Williams (Ian McShane).
Before the two men can abscond, word comes that Harry's wife Pat (Jill St. John) has been having an affair with another man and has become pregnant with the man's child. That brings the total number of scores that Harry's got to settle once he's on the outside up to two.
After a spectacular escape, the pair of hardened criminals are supposed to lie low until it's safe for them to leave the country, but a furious Harry won't allow his wife to get away with her betrayal, and he sets out to find and kill her, as well as her lover.