Miss Melody Johnson, an old unmarried lady, dies in the strange village of Plumpton Bois, once busy and prosperous, but now almost deserted and supervised by its ambitious police constable, Green, and its easy-going, cynical postman, Fowler.
Miss Johnson leaves her family home, Johnsons Place, to her sole surviving relative who cannot wait to inspect the property, but while doing so, is murdered by an intruder hiding in the cellar.
The police officials in the nearby country town cannot agree about the motive for the crime. Some say a casual burglary, other believe it to be something more subtle, since although Miss Johnson seemed to be wealthy, in reality her declared estate was next-to-nothing.
What had happened to her fortune? The Chief Constable sends for Scotland Yard to settle the argument.
Superintendent Littlejohn and Inspector Cromwell set about the mystery in their usual painstaking way and bring to light some strange facts both about the Johnson family, and some of the other inhabitants of Plumpton Bois.
Littlejohn brings the many threads together, but another sudden death threatens to break the strands and provide the killer with a way of escape.
Intruder in the Dark was originally published in 1966.