Down-on-her-luck Lori Shepherd thought Aunt Dimity was a pretend character in her mother’s bedtime stories … until the Dickensian law firm of Willis & Willis offers the possibility of large inheritance — if she can discover the secret hidden in letters between Dimity and her mother.
(Synopsis from Goodreads)

When I was growing up, I use to dream someone would drop into my life with news that would change it all. A letter from Hogwarts, a wizard with a secret quest, a mysterious house with a magic clock…
The older I get the less likely any of those scenarios are to happen (but I haven’t written them off completely!). It’s much more likely some distant relative of mine will die. And—if I’m lucky—leave me an inheritance that sends me on the adventure of a lifetime.
This series starter isn’t quite fantasy and isn’t quite mystery, but exists somewhere between the two. A haunted house, a handsome lawyer, and a woman whose life has gone of track for reasons she can’t quite pinpoint come together to uncover a secret.
Buried way in the backlist with an original pub date of 1994, I’ll be catching up on this one in front of a fire with the WiFi turned off and only a corded phone to connect me with the outside world.