Previously filmed in 1928, the old Edgar Wallace novel The Terror was dusted off for another cinematic go-round ten years later. A spectacular crime spree, instigated by a mysterious miscreant known only as "The Terror", has galvanized Scotland Yard into action. The trail of clues leads to a ramshackle old castle, owned by retired Army doctor Col. Redmayne (Arthur Wontner). The detective on the scene is one Mr. Goodman (Wilfred Lawson), who has devoted 10 years of his life to bringing The Terror to justice. Among the suspects are such low-lifes as Ferdie Fane (Bernard Lee) and Soapy Marks (Alastair Sim), but the identity of The Terror comes as quite a surprise to all concerned (except for those dyed-in-the-wool mystery fans who pegged the villain's identity as the credits unreeled!)