One early November morning, Detective-Sergeant Bert Martin of Lulverton police station in Downshire takes an alarming telephone call from a seemingly unhinged Sir Victor Warringham, claiming that a ghost has attempted to strangle him during the night.

Such is Sir Victor’s standing in the community, Inspector Charlton and Martin follow up this extraordinary report immediately by visiting Elmsdale, his country estate. Their early investigations are thwarted by various members of the household, who are none too keen to help the police – for reasons that soon become apparent.

However, while investigating this spectral occurrence, something altogether worse takes place…