Sherlock Holmes has always been the smartest man in the room, until now. There is a new criminal mastermind at large, Professor James Moriarty, and not only is he Holmes's intellectual equal, but his capacity for evil, coupled with a complete lack of conscience, may give him an advantage over the renowned detective. Holmes's investigation into Moriarty's plot becomes more dangerous as it leads him and Watson out of London to France, Germany, and finally...

Returning to his family's manor house on the lonely moors after his father dies under mysterious circumstances, Sir Henry Baskerville is confronted with the mystery of the supernatural hound that supposedly takes revenge upon the Baskerville family. The famous detective Sherlock Holmes and his assistant Dr. Watson are brought in to investigate.

Sherlock Holmes battles his arch rival, Professor Moriarty, who has kidnapped the inventor of a new bombsite.