Originally published by the same publisher in 1968.

Stolen letters -- Vanished money -- A baffling note -- Doubtful inheritance -- The mysterious gift -- A good lead -- The wrecked car -- Disheartening request -- "He's not a suspect!" -- Search for a bride -- The strange messages -- A fresh puzzle -- Locked in -- Elusive niece -- A worse mix-up -- Mistaken identity -- Fake summons -- Shakespearean puzzle -- A trap -- Shattered bells.

Nancy receives a letter meant for a British heiress who has the same name and, in her attempts to contact the other young woman, faces danger from a man who operates a Lonely Hearts Club mail fraud.