In fog-bound London, Holmes and Watson are surprised by a visit from Mycroft Holmes - Sherlock's brother and the indispensable secret power behind the British government.

A young clerk named Cadogan West has been found dead on the Underground tracks with top-secret submarine plans in his pocket.

With the security of England at stake, Holmes must determine whether West was a traitor or if there's more to this strange case than meets the eye.

A Noiser production, written by Sir Arthur Conan Doyle.

Narrated by Hugh Bonneville

Produced by Katrina Hughes and Addison Nugent

Sound Design and Audio Editing by Miri Latham, Anisha Deva and George Tapp

Compositions: Dorry Macaulay and Oliver Baines

Mix & Mastering: Cody Reynolds-Shaw and Liam Cameron

Series Consultant: Dan Smith

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