John Mannering, a retired jewel thief known as 'The Baron', owns an upmarket antique shop 'Quinns' in London's Mayfair. He is asked to value a collection of jewellery and objets d'art belonging to the estate of Ezra Peek. What is mysterious, however, is a woman who is following him as he moves around London. Then there is an attempted robbery at Quinns, with Mannering's wife tied up and locked in a cupboard. How are these events connected and when the woman declares her love for Mannering, just what is the motivation? There is danger, excitement and adventure aplenty in this, the last novel in the 'Baron' series.