Returning from a business trip, toy salesman Simon Scott is caught attempting to smuggle a wristwatch bought for his wife's birthday through Customs. He is arrested and, due to a bungled defence by his solicitor, obliged to serve a three-month prison sentence. It is only the beginning of his woes; his employer, Colonel Wilson, is understanding, but he is ultimately forced to sack Simon, who discovers that finding another job under such circumstances is extremely difficult. But Colonel Wilson is determined to help his former employee find a solution.
When young reporter and amateur biker Jerry Marsh investigates a mysterious hooded figure on a motorbike, he discovers crooks hiding out in a ruined castle with atomic sabotage on their minds...
Two men working on the docks close to London's Tower Bridge find the body of an unidentified man floating in the Thames. The police later identify the body to be that of a diamond courier from Holland. The police have to find his murderer, as well as the missing diamonds he was carrying.
An actress, urged by her detective boyfriend, takes a job as housekeeper for a wealthy elderly woman. The woman's new young husband claims she's ill and refuses entry, raising suspicions about her whereabouts.
A crooked prince uses a death ray to force down airships and steal their cargo.