Tom Poston stars as an American who sells cars in England. One night he gets an invitation to spend the night at the house of a very weird customer and good friend named Casper Femm who has a twin brother named Jasper.
Poston's character Tom Penderel takes up the offer and travels to Femm house and finds murder and much more bizarre-ness going on. Once there he is introduced to the members of the family including, Roderick Femm (Robert Morley), young and innocent Cecily Femm (Janette Scott), Agatha Femm (Joyce Grenfell), Potiphar Femm (Mervyn Johns) and the very sultry and gorgeous Morgana Femm (Fenella Fielding).
Potiphar is always claiming that the world is going to end, and he is building and Ark out in the back yard! This is just the tip of the iceberg of strange things Penderel discovers at the old house.
Castle does a good job with this film, and it never fails to entertain. Turn off your brain and enjoy a fun filom that is only around to entertain, nothing more. I do have to admit that Fenella Fielding is simply stunning in this film as she was in the classic "Carry On Screaming".