After her grandson's death, an old woman consults Holmes, after refusing a strange offer to buy her house including all its contents.

When Victor Savage begins using opium and behaving strangely, his wife consults Holmes. Victor dies, and Holmes suspects his cousin, knowledgeable in rare diseases.

Holmes and Mycroft investigate the murder of a professor's assistant who died clutching a woman's pince-nez.

Mrs. Hudson asks Holmes to help her friend with a lodger who insists on nobody entering his room, and his secret past is uncovered.

Mycroft investigates when the Mazarin Stone is stolen from a museum, and Watson deals with the promise of a large inheritance if a third person with the surname of Garrideb can be found.

When Susan Cushing is sent two severed ears, Holmes connects the case with her missing sister.