Bartholemew Sholto is working in his laboratory when a pygmy-like native fires a poison dart with a blowpipe into the back of his neck, killing him instantly. A one-legged accomplice joins the native by climbing up through the window and places a note on the dead body that reads; 'The Sign Of Four'. So begins one of Sherlock Holmes' most exciting adventures, as a Miss Morston, who is looking for her missing father, draws him deeper into the mystery. Holmes attempts to discover the meaning of those four cryptic words, with the help of his superior brain, his amazing talent for disguise, the gang of street urchins he employs called the Baker Street Irregulars, and his friend and chronicler Dr. Watson.