The Department of Curiosities: For the Good of the Empire — Karen J. Carlisle

Miss Matilda Meriwether has a secret. Actually, she has several. One of them has shaped her adult life. Another now controls it.
Her Majesty Queen Victoria has control of the Empire. She is the Empire, and creator of its secrets.
Sir Avery works for The Department of Curiosities - the keepers of secrets - especially if they are useful to the Empire.
When Tillie finds herself in the employment of The Department of Curiosities, she realises this is the perfect opportunity to uncover the truth she has been searching for.
But the Queen has other plans for her.

The Department of Curiosities is a steampunk tale of adventure, a heroine, mad scientists, traitors and secrets.
All for the good of the Empire.