Of Turtles and Doves - The Longleigh Chronicles, #7

Craving turtle soup, Jason Longleigh runs into a dainty but determined American heiress, who begs him not to eat turtle. Foolishly, he spends his allowance buying Miranda Clary two Galapagos tortoises that must be transported to his family home, along with her greedy father and fierce brother. Sparks fly when his abolitionist sister, Pandora, discovers the Clarys are slave holders, though Daniel Clary has only one.
When Mr. Clary learns Jason is penniless, the match is off. The couple flees into the night. All pursue them, impeded by voodoo spells and their flight to America. More trials await Jason and Miranda, but also Pandora and Daniel.