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 Katy Wix as Nurse Cornish Toby Jones as Culverton Smith Georgina Rylance as Carmelia Gina Bramhill as Faith Matthew Romain as Nervous Andrew Asheq Akhtar as Sahaad Vijay Doshi as Gavin Martin Savage as Ivan Ben Abell as Indignant Man Miranda Hennessy as Reporter Eric Koflabrefa as Policeman Lee Knight as Reporter Dominic Borelli as Husband Sharon Ballard as Policewoman David Kirkbridge as Policeman Usman Akram as MI5 Agent Eileen Dunwoodie as Wife
