John Mannering (aka 'The Baron') bought the Dellamont Emeralds in Paris. They were beautiful, expensive - and sinister. But Mannering, connoisseur of precious gems, chose to ignore their history of misfortune. Then things began to happen - an attempted robbery of the famous jewels; and a quarrel with Lorna Fauntley. Seemingly separate incidents, yet all connected. The strangest thing of all was that someone was impersonating the Baron ....