When Mortimer Tregennis is found dead under the same terrifying conditions as his siblings, Holmes realises the case is far from over. A strange substance, a smoking lamp, and a private experiment lead him to the truth—but at a terrible cost. And as the final pieces fall into place, Holmes is forced to choose between justice and the law.  

A Noiser podcast production. 

Narrated by Hugh Bonneville 

Written by Sir Arthur Conan Doyle 

Produced by Katrina Hughes  

Script Supervisor: Addison Nugent 

Sound Design and Audio Editing by Mirianna Pitman Latham

Sound Supervisor: Tom Pink 

Compositions: Dorry Macaulay and Oliver Baines 

Mix & Mastering: Josh Latham

Series Consultant: Dan Smith 

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