Paul Touvier led a pro-Nazi paramilitary police unit in wartime Lyon, hunting down Jews and resistance fighters with an enthusiasm that earned him the nickname the Hangman of Lyon. This episode of the Nazi Hunter series traces how a devout Catholic war criminal evaded justice for decades by taking refuge within the French Catholic Church, sheltered by sympathetic clergy who saw him as a victim of political persecution rather than a murderer. By 1988, Touvier is still free, and French investigator Jean-Louis Recordon is assigned to finally track him down. The film combines period photographs, wartime documents, and interviews to reconstruct both the atrocities Touvier committed and the decades-long cover-up that protected him, ending with the manhunt that finally brought France's most notorious surviving collaborator to trial. It is a study of how institutional protection, not just personal cunning, can let a war criminal disappear in plain sight for forty years.