Mary Morstan has received a pearl in the post every year since her father's disappearance. This leads Holmes and Watson to the truth about a secret pact between four convicts during the Indian Rebellion of 1857.

• Granada Television
• Jeremy Brett
• Edward Hardwicke
• Jenny Seagrove
• Ronald Lacey
• John Thaw
• Emrys James
• Alf Joint
• Kiran Shah