Amelia goes under cover to search for clues at Clara's home; Sherlock goes to prison under pretense of meeting his forever foe, Moriarty.

Cast: David Thewlis, Blu Hunt, Ardal O'Hanlon, Mary O'Driscoll, Hyoie O'Grady, Aisling Kearns, Savonna Spracklin, Gia Hunter, Ivana Miličević, Phillip P. Keene, Joe Klocek, Dougray Scott