A body in a priest hole. A surgeon under arrest. And a detective who needs him to be innocent.

Oxfordshire, 1925. Roderick Fane has decided to pursue surgery to remove the shrapnel lodged near his spine since the war. Only two surgeons in England are capable of the operation. One never answered his letter. The other — Mr Edwin Cathcart — has invited him to his Tudor manor for a consultation.

During a tour of the house, Cathcart shows Fane and his partner Nell Blackwood the priest hole. Inside is the body of Mr Laurence Ashford, Cathcart's professional rival — the surgeon who never replied. Dead a week. The police have their man: the public argument, the hidden room, the obvious motive. Open and shut.