Celia Lamprey looks out across the rooftops of Aleppo for the last time. After ten years living in the Orient, she and her husband, Paul Pindar, are setting sail for England - taking with them the legendary diamond, the Sultan's Blue, despite the curse that surrounds it. They arrive to find a country much changed; Bishopsgate, once surrounded by fields, is now a muddy thoroughfare choked with carriages - from which carpenters, gardeners and footmen descend, summoned to restore Pindar's great house to its former splendour. But all is not as it seems. Celia is frail, and the marriage childless. Between the couple lies a great, unspoken darkness. Now, as they await the arrival of Celia's friend Annetta from Venice, another woman, the alluring widow Frances Sydenham, becomes increasingly indispensable to the running of the household - and the happiness of its inhabitants. But who is this strange woman, and what are her real motives?