Set in England, The Executioner stars American actor George Peppard as John Shay, a British spy. Shay is convinced that there's a double agent at large, and he's further convinced that it's his former colleague Adam Booth (Keith Michell). Having set himself up as judge and jury, Shay now intends to act the part of executioner. Also figuring into the proceedings (and displaying various degrees of guilt and innocence) are Joan Collins, Judy Geeson and Oscar Homolka. The talky script isn't given much in the way of visual dynamics by director Sam Wanamaker, but The Executioner manages to sustain an acceptable level of tension.