Benedict Cumberbatch Sherlock Holmes Actor Martin Freeman Martin Freeman Actor Rupert Graves Dectective Inspector Lestrade Actor Una Stubbs Mrs. Hudson Actor Louise Brealey Molly Hooper Actor Zoe Telford Sarah Sawyer Guest Star Gemma Chan Soo Lin Yao Guest Star Al Weaver Andy Galbraith Guest Star Bertie Carvel Sebastian Wilkes Guest Star Daniel Percival Eddie Van Coon Guest Star Paul Chequer Dectective Inspector Dimmock Guest Star Janice Acquah Museum Director Guest Star Jack Bence Raz Guest Star Olivia Poulet Amanda Guest Star Howard Coggins Brian Lukis Guest Star Euros Lyn Director Mark Gatiss Writer, Executive Producer Steve Thompson Writer Beryl Vertue Executive Producer