A young woman goes to an isolated Warwickshire monastery to visit her brother, who is a monk there. Her sister drops her off at the door. The girl meets her brother in the parlour; they say goodbye and part; and she is never seen again. A search of the buildings and grounds finally reveals her body buried in a shallow grave in the monastery cemetery. The monks, however, have a cast-iron alibi: they were all in chapel at the time of her death. Then the abbot receives a mysterious telephone-call. A man’s voice threatens to hand evidence of the murder to the police – and so incriminate one of the monks - unless the monastery puts up for public auction its most treasured possession, a unique mediaeval manuscript, and donates the proceeds to charity. Is this blackmail or a hoax? As the events unfold, the inspector and his sergeant become less and less sure of what is fact and what is fiction, and the inspector begins to fear for his newly-won promotion. The case takes him to a castle in Italy, a town-house in southern France, a laboratory in Cambridge and the home of a professor of music outside Lincoln; but the solution arrives unexpectedly in his own sitting-room. In this stylish story written in the classic tradition of British detective fiction, the author intrigues, informs and entertains in equal measure.