Although the demure young beauty, Kezia Falcon, and her brother Peregrine are part of an ancient and noble family, they are all but bankrupt despite all their efforts. Nevertheless the handsome Perry continues to socialise and gamble at cards in London while Kezia lives alone but for the old butler in the family's charming but dilapidated house in the country. Suddenly it seems that their fortune may change when Peregrine finds an unexpected buyer for their one precious heirloom, which is a beautiful necklace made with diamonds stolen from the legendary 'Queen Marie Antoinette Necklace', which had created a huge scandal just before the French Revolution broke out. The prospective buyer is the tall, handsome and impressive French Marquis de Bayeux who is coming on a visit to England to view the necklace. But, because he is apparently a notorious Don Juan with whom no woman is safe, Peregrine insists that they pose as a married couple instead of being brother and sister for Kezia's protection. This is a charade that they will come to regret when the dashing Frenchman inspires in Kezia not fear or dread but awe and admiration and then finally, ¬love.
