Michael Weston Harry Houdini Actor Stephen Mangan Sir Arthur Conan Doyle Actor Rebecca Liddiard Constable Adelaide Stratton Actor Sian Breckin Margery McGuire Guest Star Emily Carey Mary Conan Doyle Guest Star Will Chambers Patient Guest Star Stephen Colledge Protestor Guest Star Shane Crehan Claude Debussy Guest Star Angela Curran Vera Guest Star Gary Davies PC Chris Johnston Guest Star Jennifer Day Funeral Attendee Guest Star Michael Deighton Working Class Man Guest Star Laura Fraser Lydia Belworth Guest Star Samuel Joslin Peter Bennett Guest Star Noah Jupe Kingsley Conan Doyle Guest Star Matt Lanigan Frank Bennett Guest Star Ruth Lass Clara Bennett Guest Star Andrea Lowe Beatrice Upton Guest Star Phil Nice Reverend Gilby Guest Star Conny Sharp Amanda Posh Guest Star David Shore Executive Producer Kenton Allen Executive Producer Matthew Justice Executive Producer Luke Alkin Executive Producer Christina Jennings Executive Producer Maggie Murphy Executive Producer Scott Garvie Executive Producer