Mr. Verloc is part of a gang of foreign saboteurs operating out of London. He manages a small cinema with his wife and her teenage brother as a cover, but they know nothing of his secret. Scotland Yard assign an undercover detective to work at the shop next to the cinema in order to observe the gang..
Joseph Conrad (novel), Charles Bennett (screen play), Ian Hay (dialogue), Helen Simpson (dialogue), Alma Reville (continuity), E.V.H. Emmett (additional dialogue)