London: January 1958. During the past two and a half years a serial killer has been roaming the streets of London torturing his victims by slicing off their left ear before ritually disembowelling them. Detective Inspector Neil Goddard, a lonely man who has never really got over the death of his fiancee in 1951 and assigned to catch the murderer is woken early one morning to be told that another body has been found but to his surprise learns that it is actually the killer himself. Identification is soon established but investigations into what turned the man into such a callous monster and to who had killed him leads Goddard back to old haunts and revives memories of events that happened during the early years of the Second World War. The situation is further complicated when a telephone call is received which states that the revenge killing was a way of repaying a debt owed to him - and evidence points to the debt referring to one specific event seventeen years earlier. Recognising that what had happened during a clandestine operation into occupied France is the key to finding out the identity of the 'vigilante' Goddard soon finds himself immersed in the world of espionage and meets Gerald Fitzroy-Browne, a man who is hiding a secret. During the discussion he learns that the key character is Lionel Preston, a habitual criminal who was recruited in 1940 into a shadowy force known only as Group 'A', part of the Special Operations Executive. Although the unit was supposed to have been disbanded in 1945 this group continued under different auspices without sanction from the Government and Preston, known under many pseudonyms associated with the works of H G Wells, carried out a number of obscure assassinations but latterly seems intent on maintaining his anonymity by killing those few people who can identify him, which includes Winston Churchill. Goddard, realising that time is running out, then learns that the man behind the wheel in the hit and run accident that had killed his fiancee was actually Preston and redoubles his efforts to catch him. But when documents come into his possession that show she was working for the French Government under the code-name The Silent Butterfly and had been close to exposing the truth behind Group 'A' he realises that he had been duped on more than one occasion and begins to doubt all that he had been told as well as Preston's role in it and latterly. In an unexpected finale he finds out he had also been lied to by Fitzroy-Browne and learning that friends and enemies are often one and the same and that nobody can really be trusted he is powerless to stop old scores being settled."