In late 1876 Sherlock Holmes returns to London to begin his career as a detective. Within weeks he solves the murder of the manager of a theatrical company and exposes corruption within Scotland Yard. However, he gets little credit for either and has difficulty attracting new clients. He spends his time improving his many skills and solving cases for the challenge.

In time clients come. Follow Sherlock Holmes as he searches for the criminals behind the Turf Fraud, hunts down the Blackheath Burglar, finds the Opal Tiara, discovers the hidden meaning in the Musgrave Ritual, finds out the secret of the Aluminum Crutch, and stops the Giant Rat of Sumatra from reaching England. Plus many more cases before he meets his friend and biographer, Dr. John H. Watson.