The Vanished Messenger

A man vanishes from a Norfolk inn between the fish and the entrée, leaving a hundred thousand pounds and a mission from an American millionaire undelivered — and the guests who watched him go have their own reasons for it. Oppenheim wrote some hundred and fifteen thrillers and invented the international-intrigue novel as a form; this 1914 one is the clean machine, and the Norfolk coast in it is genuinely cold.