The suspects are the guests at the house of the local Lord, the thirteenth being the unfortunate John Foss who spends most of the book lying on a couch with a twisted ankle. This does allow him to experience some of the odd goings on in the house at night.
These include a vandalised painting, a dead dog and then some dead people. The police in the form of Inspector Kendell then has to unravel the complicated lives of the guests at the house and try and discover just what has been going on.
A decent mystery so full of Golden Age tropes it might approach self-parody at times but a witty good read. The characterisations are well drawn and the investigation ends with a bit of an unusual twist.
