Key plot details
- Miss Mary Morstan arrives and asks for help with a mystery.
- Holmes and Watson accompany her to Thaddeus Sholto's house and learn about the Agra treasure.
- Bartholomew Sholto is found dead at Pondicherry Lodge.
- Holmes investigates the clues and calls the police. Athelney Jones arrests Thaddeus Sholto. Holmes sends Watson to borrow Toby, the dog.
- Holmes employs the Baker Street Irregulars as spies and eventually puts on a disguise to track down the Aurora launch.
- Watson, Holmes and Inspector Jones pursue the villains along the River Thames and catch up with them. The treasure chest is empty.
- Jonathan Small is arrested and confesses his whole story. Watson and Mary Morstan are engaged to be married.