The work of Peter Ketley on Fisheries Research in Devon is being disorganised by a mysterious new method of salmon poaching. His young brother Bob, with the help of two children from London, eventually uncovers and catches the poachers.
as Bob Ketley
as Susan
as Simon
as Peter Ketley
as George
as Tom
as Arnold
as Mr. Atherton
as Mrs. Atherton
as Quarryman