The movies are made close to the plot of the books, but have some notable, and sometimes quite humorous differences, e.g. Dr. Watson within first weeks of living in Baker Street was trying to figure out what was Holmes profession.

Happy to demonstrate his profession, Holmes has Watson sit in with his next client, a fearful young woman named Helen Stoner.

He beats it back with a cane and breaks into Roylott's room, where the trio find that the enraged snake had returned and fatally bitten its owner.

Lestrade tracks down Drebber's correspondent and rival, Joseph Stangerson, as the main suspect, only to find him stabbed to death in a hotel room.

Watson reads a report on the case in the Times but is angered to find the credit had been given entirely to Gregson and Lestrade, and vows to write down Holmes' stories to be popularized across the world.