Ethelred Tressider, the mediocre mystery author we first met in The Herring Seller's Apprentice and Ten Little Herrings, and his bossy, chocolate-loving agent, Elsie, are to dine with Ethelred's old friend, Sir Robert (known to his friends as Shagger) and Lady Muntham. Elsie doesn't think much of her hosts, but she is very much interested in figuring out who killed Sir Robert once he turns up dead in his locked library. A delightful parody of the country house mystery.