The Three Locks by Bonnie MacBird
The Three Locks is the fourth in MacBird's Sherlock series, but can be read as a stand-alone. She puts her own spin on the classic characters and she brings the era to life well.
The story begins with Dr. Watson receiving a mysterious box, supposedly from his mother, who has been dead for many years. It's locked with the first of the three locks, a lock no one can open and for which Watson doesn't have the key.
Soon, Sherlock and Watson are approached by the first client, the wife of an Italian escape artist. She wants him to discover the truth behind the feud between her husband, The Great Borelli, and a rival magician. That night, one of Borelli's acts goes wrong. He escapes, but barely. So, the second lock is involved in the magic tricks.
Another client presents the third lock. Peregrine Buttons, a young Catholic deacon, asks Holmes to find a missing young woman, the strong-willed Odilie Wyndham,...