Guest Stars Rupert Graves as DI Lestrade Una Stubbs as Mrs. Hudson Louise Brealey as Molly Hooper Mark Gatiss as Mycroft Holmes Andrew Scott as Jim Moriarty Amanda Abbington as Mary Morstan Simon Kunz as Sir Edwin Sian Brooke as Eurus Holmes Wanda Ventham as Mrs Holmes Timothy Carlton as Mr. Holmes Ralph Ineson as Vince Tam Mutu as Leonard Harry Tuffin as Victor Trevor Matt Young as Young Police Officer Indica Watson as Little Eurus Brett Allen as Special Unit Guard Aaron Richards as Young Mycroft Clare Foster as Velma Art Malik as Prison Governor Richard Crehan as Ben Paul Weller as The Viking Rhys Rusbatch as Technician Tom Stoughton as Young Sherlock Honor Kneafsey as Girl on Plane
