Holmes and Watson are retained by the Duke of Salcombe after the death of his father. A letter kept secret for many years holds a clue to a great treasure with a terrible past. They must seek out a military link to the late Duke and the events that lead to the discovery and then disappearance of the 'Star of Bithur'.Treachery in India during the Indian Mutiny of 1857 and the disappearance of the gem are closely linked. An attempted burglary to steal a family painting at Salcombe Grange alerts Holmes to the importance of the painting and the secrets it holds. Holmes and Watson are invited to Salcombe Grange to view the painting and valuable clues are gleaned regarding the identities of the burglars.An attempt is made to unearth the gem but the old Duke has created an enticing puzzle that only a superior intellect can solve.