White Magic (Topaz Historical Romance)

In Regency London, a young lord sets out to discover the circumstances surrounding his friend's suicide by locating the lady who spurned him. What he finds is an enchanting woman with some peculiar hobbies: nocturnal activities the lord believes to be sorcery, and an affectionate relationship with a wealthy gentleman. But nothing prepares him for the most startling revelation of all--a passion that suddenly consumes them both.