A man dies suddenly of a mysterious fever, and Holmes suspects murder.

Mrs Warren, a London lodging-house keeper, comes to Holmes with a curious story of a reclusive and eccentric tenant. Mrs Warren's husband has been abducted and then quickly released again, perhaps a case of mistaken identity. Holmes decides the case is more important than it appears.

When Susan Cushing first consults Holmes about the disappearance of her sister Mary, he shows little interest in the case. But then, at Christmas, Susan receives an alarming present in a cardboard box, and Holmes is quickly on the trail of a dangerous criminal.

The police are baffled by the murder of Willoughby Smith, and Inspector Hopkins looks to Holmes to solve the case.

The Mazarin Stone, a famous jewel, acts as a magnet for crime. Holmes investigates the latest and perhaps most curious episode in its adventures.

Holmes investigates when a man dies and the manuscript of his recently-completed book is stolen. He has to discover who was behind an unusual proposal to buy a house and all of its contents.