American adventuress Beryl Halliwell and prim and proper Brit Edwina Davenport team up once again as enquiry agents to investigate a suspicious psychic in this historical English village mystery set just after World War I.

Hidden beneath her British reserve, Edwina has a secret: she's finished her novel and is bravely mailing the manuscript to a publisher. Beryl also has a secret: as thanks for solving a case, the American adventuress has been gifted an airplane. After swooping over the fields and hedgerows of Walmsley Parva, livestock scattering beneath her, she flamboyantly lands the plane on the village green, prompting a startled Edwina to consider a stiff gin fizz.

Beryl's aircraft is not the only disruption of village peace. Miss Dinsdale, a psychic medium, has started holding séances. After the church organist resigns to serve as musical accompaniment for the séances, the vicar's wife hires the enquiry agents to expose the medium as a charlatan. Beryl is confident she can spot the fraud, having learned from Harry Houdini himself some tricks of the trade. The dubious Miss Dinsdale claims her spirit guide is an Egyptian princess whose mummy resides in a sarcophagus in the room. But the only body in the sarcophagus belongs to a murdered villager impaled with a dagger.

As the sleuths begin to investigate, Beryl discovers her plane has been sabotaged and wonders if there's a connection. Whether in the air or on terra firma, Beryl and Edwina must go round a circle of suspects to divine the culprit . . .