Criminals have kidnapped Seargeant Miller's daughter Cheryl and threaten to kill her if he doesn't do what they say. And under no circumstances is he to tell anybody. But both Alf Ventress and PC Mason soon suspect that something is wrong. Protesters demonstrate against the French politician Michel Dubois who is at a conference in the area. He is said to have been a Nazi collaborator during the war and Special Branch fears there may be an attempt on his life during the conference and asks the police for backup. The gunman may be the mysterious Frenchman staying at the Aidensfield Arms - or are the people holding Miller's daughter involved? Aunt Peggy is not feeling well and Nurse Cassidy can only tell her to see a doctor. But although Peggy thinks she has one one foot in the grave already she is very reluctant to take such a drastic step.