Guest Stars Emily Carey as Mary Conan Doyle Noah Jupe as Kingsley Conan Doyle Tommy McDonnell as Nigel Pennington Blake Harrison as Lyman Biggs Sebastian Croft as Newsie Mary Healey as Mrs. Blake James Lance as Barrett Underhill Dean Forster as Herbert Ogilvie Natasha Sparkes as Sophie Helen Millar as Isobel Underhill Tereza Srbova as Natalia Kroshenko Scott Jenkinson as Spring Heel'd Jack Paddy C. Courtney as Gaines Craig Conway as Angus Tuttle Dritan Kastrati as Vladimir Patlinov