"An interesting bargain, is it not? A pact of honesty between a woman said to have murdered her husband in cold blood and a gentleman who conceals the truth about himself from the world."
"I am satisfied with it." (p. 86)
Madeline Deveridge is the eponymous Widow, and now she is apparently being haunted by the ghost of the husband she's alleged to have murdered. She applies to Artemas Hunt, brilliant recluse and owner of the Dream Pavilions (London's favourite pleasure emporium), for help -- well, actually, she blackmails him, because no gentleman would wish it to be known that his wealth comes from trade.
Hunt is engaged in a labyrinthine vengeance against the men who killed his lover: at first he has little interest in Madeline's woes, but soon enough he begins to respect her sharp wits and general competence. Besides, she has further blackmail material: her father's journals, which record a great deal of information about the members of the Vanzagarian Society, including Hunt himself.
Madeline, blithely oblivious to the thousand-pound bet that no man can survive a night with her, is busy with a translation of an ancient book that's come into her possession. It can't be the notorious Book of Secrets that's lately gone missing: but perhaps it is equally valuable, to somebody.
This is Regency Lite -- set in London, but a London with none of the usual familiarities. Indeed, it's possible that this is also Fantasy Lite: much of the plot revolves around the mysterious Vanzagarian Society (ladies not admitted) based on the esoteric philosophy of an ancient sect. It's an easy, frivolous read, with some unexpected twists and a satisfactory romance.
Yes, I did read it solely because the author's surname began with 'Q': but I don't regret discovering Ms Quick's writing.