Guest Stars Rupert Graves as DI Lestrade Una Stubbs as Mrs. Hudson Louise Brealey as Molly Hooper Mark Gatiss as Mycroft Holmes Amanda Abbington as Mary Morstan Sian Brooke as Eurus Holmes Lindsay Duncan as Lady Alicia Smallwood Tom Brooke as Bill Wiggins Toby Jones as Culverton Smith Georgina Rylance as Carmelia Katy Wix as Nurse Cornish Asheq Akhtar as Sahaad Gina Bramhill as Faith Matthew Romain as Nervous Andrew Usman Akram as MI5 Agent Vijay Doshi as Gavin Martin Savage as Ivan Miranda Hennessy as Reporter Ben Abell as Indignant Man Eric Koflabrefa as Policeman Lee Knight as Reporter Sharon Ballard as Policewoman David Kirkbridge as Policeman Dominic Borelli as Husband Eileen Dunwoodie as Wife
