*‘Should detectives go to parties? Was it consistent with the dignity of the Yard? The inspector tossed for it - and went.’* Chief Inspector Macdonald has been invited to a treasure hunt party at the house of Graham Coombe, the celebrated publisher of *Murder by Mesmerism*. Despite a handful of misgivings, the inspector joins a guest list of novelists and thriller writers disguised on the night under literary pseudonyms. The fun comes to an abrupt end, however, when ‘Samuel Pepys’ is found dead in the telephone room in bizarre circumstances. Amidst the confusion of too many fake names, clues, ciphers, and convoluted alibis, Macdonald and his allies in the C.I.D. must unravel a truly tangled case.