Synopsis
A mystery unfolds in a quiet London suburb, where Karl Anton Verloc (Oskar Homolka) and his wife (Sylvia Sidney) are the owners of a small cinema. Unknown to Mrs Verloc, her husband has a secret that could not only affect their relationship but be a deadly threat to her teenage brother who lives with them. Scotland Yard have information that the unassuming Karl Verloc is in fact a saboteur and is about to put into action a plan that, if successful, would cause wide-scale injury and death in the capital. The Yard has to thwart his evil ambitions at all costs but the problem is finding out how and where he will plant his deadly weapon.
