Penny for Your Secrets by Anna Lee Huber

Verity's friend Ada was not born into the aristocracy but she did marry into it. AT Ada's for a dinner, Verity is dismayed to find that the relationship, which had lasted for 5 years before their marriage is now, two years after marriage, in disarray. They can barely hide their animosity and most of the guests are ready for the show, including Ada's marked preference for another man.  At dinner, Ada plops a gun on the table and "jokes" that she might shoot her husband. The butler quickly removes it but Verity is shocked to find out that the gun was not put in the chair by Ada. This seems very suspicious but no one else is worried. However, when Lord Rockham is murdered, Ada immediately becomes suspect number one.
But Verity won't be able to work on just one murder. One of her friend's half-sister died and the friend is certain it was murder. The dead woman was one of the people who worked for the Royal Mail, redacting information from soldiers to home. It is very likely that she saw something that could have gotten her killed.
There is a lot of development between Verity and Sydney as they try to find their way through their marriage, both having made mistakes. They were only married for 3 days before he went to war. She thought he died and he thought she stayed home while the truth was, she went into the secret service.
A great addition to the series, even if it does end with Verity realizing she's found her very own Moriarty. Not a cliffhanger per se, but there are definitely things unresolved.

Four stars

Followed by A Pretty Deceit
This book came out October 29th
ARC kindly provided by Kensington Books and NetGalley
Opinions are my own