Lots of slogans such as "Be like Dad, Keep Mum" and "Keep it under your Hat" are visible on the walls in various scenes to reinforce the plot of this British wartime movie illustrating how gossipy talk can result in unknowingly giving valuable information to Nazi spies.

During a charity football match between Arsenal and touring amateur side Trojans, the Trojan's new star player collapses and dies. Inspector Slade of Scotland Yard is called in and declares it was murder. It takes all his ingenuity and another death before the motive is discovered and the killer revealed.