Sir John Appleby, retired Chief Commissioner of Metropolitan Police, was taking a country walk when he had a curious encounter with the lord of a neighboring manor, the aged Martyn Ashmore. Ashmore, in a state of belligerent fear, accused Appleby of having designs on his life.
Probing a little, Appleby learned that during the war Ashmore had cracked under Nazi torture, which led to the massacre of many Resistance fighters, and ever since, on the anniversary of that day, an attempt was made on his life. Sir John believed the old man was given to senile delusions until the two of them narrowly escaped death as a large stone block fell from the roof of the house.
A murder does take place and not only Sir John but his engaging undergraduate son Bobby was involved in the investigation that followed. Michael Innes has half a dozen surprises up his sleeve, and the story is told with immense zest and high spirits.