Scandal Above Stairs by Jennifer Ashley

Priceless artwork has gone missing from the home of a wealthy baronet, and his wife stands to take the blame. When Kat’s employer asks for help in clearing her friend’s name, Kat trades her kitchen for the homes of Mayfair’s wealthiest families.

Soon antiques are disappearing not only from the extravagant households of connoisseurs and collectors, but from the illustrious British Museum. As the thefts increase in frequency, Kat calls upon her friend Daniel McAdam, who has already set himself up in a pawnshop on the Strand as a seedy receiver of stolen goods. When a man is murdered in the shop, Kat must use all of her wits to see that the thieves are caught and justice is done.