Mystery of Ruby's Sugar

A locked room.
A secret letter.
A weekend to solve a murder.
Christmas, 1934.
The snow lies heavy around Pauncefort Hall.
Fashion-spy-amateur sleuth heroes Ruby and Fina are on a mission to avenge Ruby's family and bring down an empire.
After a murderer strikes, an aristocratic family, a princess, a left-wing professor, and a West End starlet are among the top suspects.
Ruby and Fina must find the culprit and still carry out their secret plans-all before the law arrives.
But Pauncefort Hall can remain snowbound for only so long.
If you like Barbara Neely, Rhys Bowen, and G.M. Malliet, then you'll want to pour yourself a warm beverage and nestle down with The Mystery of Ruby's Sugar.