When Mrs Mildred Cobnut of Compton Poppleford Ladies Bicycling Club suffers a fatal accident, hapless Inspector Mappin begins a murder investigation. As luck would have it, world-renowned Swiss detective, Monsieur Pascal Legrand, is staying in the village; with such sleuthing expertise on hand, the case will surely be swiftly solved.

Meanwhile, Churchill and Pemberley have another case to worry about: Ramsay the missing goat. But with Churchill having crossed swords with Mrs Cobnut, the elderly detectives soon become embroiled in the murder investigation.

Who is the mystery man who calls on Mrs Twig? What causes Farmer Glossop's horse to bolt down the high street? Will Churchill ever finish a slice of Pemberley's prune cake? There are many questions for the detective duo to answer before they can hope to beat the famous Monsieur Legrand at his own game.