The Hounds of Baskerville order to test his theory. He also points out Sherlock was wrong for once; he believed the drug was in Henry's sugar and put it in John's coffee. In the closing scenes, Mycroft oversees the release of Jim Moriarty (Andrew Scott) from a holding cell in which he has written Sherlock's name all over the walls. The story is based on Arthur Conan Doyle's novel "The Hound of the Baskervilles", and also contains plot devices and lines from other Doyle stories: In June 2011, it was announced that Russell Tovey would appear in "Sherlock" series two in its second episode.
The Hound of the Baskervilles of an incompletely burnt letter asking Sir Charles to be at the gate at the time of his death. It was signed with the initials L.L.; on Mortimer's advice, Watson questions a Laura Lyons, who admits to writing the letter in hopes that Sir Charles would help finance her divorce, but says she did not keep the appointment. Watson tracks the second man he saw in the area and discovers it to be Holmes, investigating independently in hopes of a faster resolution. Holmes reveals further information: Stapleton is actually married to the supposed Miss Stapleton, and he promised marriage to