In 2009, art detective Dr Bendor Grosvenor caused a national scandal by proving that the Scottish National Portrait Gallery's iconic portrait of Bonnie Prince Charlie, the rebel Stuart who almost seized power in 1745, was not in fact him. Keen to make amends, and suspecting that a long-lost portrait of the prince by one of Scotland's greatest artists, Allan Ramsay, might still survive, Bendor decides to retrace Charles' journey in the hope of unravelling one of the greatest mysteries in British art.