Characters played by Boris Karloff
Prof. Henry Morlant
Characters played by Cedric Hardwicke
Broughton
Characters played by Ernest Thesiger
Laing
Characters played by Dorothy Hyson
Betty Harlon
Characters played by Anthony Bushell
Ralph Morlant
Characters played by Kathleen Harrison
Kaney
Characters played by Harold Huth
Aga Ben Dragore
Characters played by D.A. Clarke-Smith
Mahmoud
Characters played by Ralph Richardson
Nigel Hartley
Characters played by Jack Raine
Davis the Chauffeur
Characters played by George Relph
Doctor