Charles Bennett says the film was based on his original idea. He later admitted it was "terrible... but amusing".
Professor Heggie is determined to prove to a sceptical sciencific community the existence of a dinosaur in Loch Ness. Young London reporter Jimmy Anderson believes him and offers to help. He also falls in love with Maggie, the professor's daughter. Jimmy finally plucks up the courage to enter the Loch himself, and comes face to face with the monster.
Professor Heggie - Seymour Hicks
Angela Heggie - Nancy O'Neil
Angus - Gibson Gowland
Jimmy Anderson - Frederick Peisley
Jack Campbell, the Diver - Eric Hales
Maggie Fraser, the Barmaid - Rosamund John
Piermaster - Ben Field
Reporter - Robert Wilton
Professor Blenkinsop Fothergill - Hubert Harben
Scientist at Meeting - Fewlass Llewellyn
Macdonald - Stafford Hilliard
Judge - D.J. Williams
Reporter/Photographer in Pub - Clive Morton
Mate - Cyril McLaglen
TV Guide called the film "a trite programmer which doesn't make one believe in the humans' actions, much less the sea serpent's"; while Allmovie called it a "fairly amusing British monster movie...obscure but entertaining oddity"; and Britmovie noted an "enjoyable comic romp."