A Miss Marple Nightcap: The Four Suspects by Agatha Christie
b"This week's short story relies on both arcane technical knowledge *and* dubious cryptography, and yet it was not written by Dan Brown. Go figure. Come and sit a spell with us at Gossington Hall, at the seemingly never-ending Bantry dinner party. It's Sir Henry Clithering's turn to tell a tale, and he does not disappoint. Plus: a bonus peek at the softer side (or is it?) of Miss Jane Marple!"