Fred Mumford returns to earth from the spirit world to open a business called 'Rentaghost' which offers ghosts and poltergeists on a daily or weekly rental basis. He is sometimes helped, but more often hindered, by Davenport, a fussy Victorian ghost, and Claypole, a mischevious medieval poltergeist.
Fred Mumford and his fellow ghosts set out to exercise a ghost which has been terrorising London's Heathrow Airport.
Mumford and his colleagues decide to tell their landlord, Mr. Meaker, that they are really ghosts. The shock of this lands Mr. Meaker in the local hospital where the Rentaghost team offer to provide a conjuring act for the centenary celebrations. As ghosts they find it easy to vanish - but Mumford has some difficulty becoming visible again.
The Rentaghost team are engaged by a security firm to patrol a large department store and stop shoplifting. Claypole goes through a mischevious phase when his poltergeist powers are at their strongest.
Haunting a stately home proves to be something of a trial of strength for Mumford. His ghostly Uncle Arthur provides him with an assorted bunch of spooks to help the haunting, then calls them out on strike.