When her niece Cat travels to a wedding in Italy, Isabel agrees to fill in at Cat's delicatessen. She takes note of a customer named Ian, who is avoiding chocolate--doctors say it's bad for the new heart he recently recieved. Ian is haunted by memories he can't quite place, prompting Isabel to wonder if his new heart may be the cause. Always keenly interested in matters of the heart, Isabel investigates and discovers some rather surprising truths.