Lady Collingford has heard some noises in the mansion. Not realising that it is Catweazle snooping about.
She thinks there is a ghost and calls in ghost hunter, Hector Kenley who is a charlatan who plans to make money out of the Collingfords. He and his assistant rigs the house with electronics to make noises in the night.
Catweazle thinks the Ghost Hunters are actual ghosts and wants to find out about the hidden treasure in the house.
It all turns into a Rentaghost type romp not far removed from a famous Laurel & Hardy film. Cedric ends up scaring the ghost hunters as he joins them playing a ghost with a white sheet over his head.
Another episode where the sign of the zodiac is incidental to the main plot.
I did like Cedric teaching Catweazle the alphabet.
Dudley Foster plays Hector Kenley. He is such a familiar face as he appeared in loads of shows even though he died at a young age in 1973.