Amazon.com description: Product Description: Protecting an heiress should be an easy job for Bow Street Runner John Chase. But the heiress--daughter of rich London merchant Hugo Garrod and a slave-housekeeper on his Jamaican property--is no conventional society miss. Educated to take a place among Regency England's upper crust and marry well, she has failed at London's social scene and lives isolated among the Garrod family in Clapham. And someone is playing her malicious tricks, some of which recall her island heritage of Obeah.

John Chase needs to determine whether Marina is indeed a victim--or is herself a delusional and malicious trickster. If the trickster is real, is it her rejected suitor and cousin Ned Honeycutt? His demure sister? Their devoted aunt who acts as the Garrod housekeeper? A clergyman friend? Everyone around Hugo Garrod has a stake in how he disposes of his immense wealth.
 
Meanwhile Mrs. Penelope Wolfe, an abandoned wife, flouts convention by earning her living with her pen. She's in love with barrister Edward Buckler and hesitant to further scandalize society by breaking any more rules. Hugo Garrod invites her to join his household and put her pen to work. Her assignment takes her into an exotic world where menace lurks at every turn of the garden path and the façade of propriety masks danger.

To solve the case, Chase must grasp the enigma of Marina, an expert in self-concealment, who challenges his assumptions and confronts him with difficult truths. And, with the aid of Penelope and Edward Buckler, reveal a clever killer.  

On a Desert Shore stretches from the brutal colony of Jamaica to the prosperity and apparent peace of suburban London. Here a father's ambition to transplant a child of mixed blood and create an English dynasty will lead to terrible deeds.