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.
Sherlock Holmes

Dr. John Watson

Mary Morstan

Thaddeus und Bartholomew Sholto

Jonathan Small

Inspector Athelney Jones

McMurdo

Tonga

Captain Morstan
Mrs. Hudson

Major Sholto

Jack Smith

Lal Chowder
Williams

Mrs Bernstone
Sherman
Mrs Mordecai Smith

Wiggins
Boatyard Workman
Mordecai Smith
Kartar Singh

Achmet

Jagodish Singh