War vet Dr. John Watson returns to London in need of a place to stay. He meets Sherlock Holmes, a consulting detective, and the two soon find themselves digging into a string of serial "suicides."
Mysterious symbols and murders are showing up all over London, leading Sherlock and John to a secret Chinese crime syndicate called Black Lotus.
Mycroft needs Sherlock's help, but a remorseless criminal mastermind puts Sherlock on a distracting crime-solving spree via a series of hostage human bombs through which he speaks.
Sherlock must confiscate something of importance from a mysterious woman named Irene Adler.
Sherlock and John investigate the ghosts of a young man who has been seeing monstrous hounds out in the woods where his father died.
Jim Moriarty hatches a mad scheme to turn the whole city against Sherlock.
John and Inspector Lestrade try to move on with their lives after Sherlock's apparent death. However, Anderson believes he is alive.
Mycroft calls Sherlock back to London to investigate an underground terrorist organization.
Sherlock tries to give the perfect best man speech at John's wedding when he suddenly realizes a murder is about to take place.
Sherlock goes up against the notorious blackmailer Charles Augustus Magnussen.
Sherlock waits to see where Moriarty will make his posthumous move. One mysterious case in particular baffles Scotland Yard - but Sherlock is more interested in a seemingly-trivial detail. ...