秘密機関
Prudence ("Tuppence") Beresford, who is happily married to Tommy for six years, is bored with life. She flippantly discusses what exciting things she would wish to happen to her. Their conversation is interrupted by the arrival of Mr Carter (see "The Secret Adversary") who asks them to take over The International Detective Agency. The agency's manager, Theodore Blunt, is in prison. Carter's particular request is that they watch for letters on blue paper sent to Mr Blunt from a purported ham merchant anxious to trace his refugee wife. Each such letter will have a Russian stamp with a "16" written underneath. He asks for such letters to be sent to him immediately.