
Italian frogman and scientist Paolo Rocello is found dead on a houseboat. The owner of the boat, Mr. Cooper, has disappeared without a trace. The English boarding school town of Medlow is now in turmoil. Of all people, the likeable boarding school teacher David Henderson is increasingly suspected of murder. This is because Katherine Walter, the niece of Dr. Sheldon, saw him on the boat on the day of the murder. However, Dr. Sheldon himself also becomes a suspect. Inspector Ford and Sergeant Broderick are in the dark – until another murder occurs and a completely new perspective on the events emerges...
David Henderson

Dr. Sheldon
Katherine Walters

James Cooper
Robin Caven
Det.-Inspect. Ford
Det.-Sgt. Broderick
Judy
Billie Reynolds
Roger Ford
Ralph Merson

Mrs. Williams
Detective Morris
Polizist Sanders

Chris Reynolds
Maria Rocello
Harry Vincent
