Invalided home from the war in Afghanistan, Dr. John Watson becomes roommates with the world's only "consulting detective," Sherlock Holmes. Within a day their friendship is forged and several murders are solved.

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.