While a new street drug quietly eats away at the streets of London, the eerie death of a young noblewoman of a now-penniless family catches the eye of the Great Detective Sherlock Holmes. The twists and turns of his investigation soon uncover a crumbling estate filled with exotic beasts, an eccentric father with an unhealthy obsession toward his daughter, and a secretive tribe of nomadic Romani. But how are all of these clues connected? And what do they have to do with the mysterious “speckled band”?