In October of 1889, the formula for a new and extraordinarily powerful explosive disappeared from the Ministry of Defense. Sherlock's brother Mycroft, an eccentric but influential government servant, launched an official though secret inquiry into the theft, but his effort was thwarted. Just before asking Sherlock to undertake an independent investigation of the theft, Mycroft was seriously injured in an explosion that leveled the Diogenes Club. Sherlock, believing his brother had been victimized by a random gas leak, retired disconsolate to 221B Baker St. Dr. Watson, with a little luck and much effort, managed to reanimate his friend by posing one critical question: "What if the explosion that injured Mycroft had not been an accident?"