Sherlock Holmes and Dr. Watson to the rescue!
Violet Stoner dies under mysterious circumstances in her bedroom at the gloomy mansion of her brutish stepfather, Dr. Grimesby Rylott. Because Violet had become engaged to be married, she stood to inherit a substantial annual allowance from her parents' estate but never survived to collect it. Her last words were "The Speckled Band!"
Now, her sister Helen has become engaged, and the mercenary doctor views the event as money out of his pocket as she stands to get a yearly stipend too.
When he orders her to start sleeping in her sister's bedroom, and she finds the bed bolted to the floor, she fears that a fate similar to Violet's will befall her. She turns to the residents of 221B (er, 107) Baker Street for help.
This early talkie take on Sherlock Holmes is different from both the original Arthur Conan Doyle tales and the later Basil Rathbone/Nigel Bruce films. The great man works out of an office (at 107 Baker St., presumably just a stroll down the street from home at 221B) with three secretaries with whom he can communicate with an early intercom system from his inner office. Super-science equipment that supposedly has all the information available on every known criminal, including location, clatters away in the outer office. One secretary types up information very rapidly while listening to a non-electrical recording on a cylinder through earphones like a stethoscope. Another operates a card sorter (possibly) printing info out to paper. All very early-IBM and impressive, but not to Sherlock Holmes, who brings the head secretary to tears by continually correcting the system. Holmes prefers his own impressive equipment -- his mind!
Byron Haskin, credited with "Technical Supervision" on this film went on to a storied career which included directing The War of the Worlds (1953) and the classic Outer Limits TV episode Demon With a Glass Hand (1964)