A woman reporter discovers a former lover and intelligence officer during WWII apparently working as a waiter in a hotel; and, believing something she impulsively did while he was on a mission is responsible for his current situation, sets out to make things better by finding a foreign agent known only as Kupchek, with the help of the hotel's detective.

Katie attempts to save her father's failing garage, after he is killed during a stock car race. She is assisted by an American driver, Larry Duke, but unfortunately one of the creditors is determined to take the garage.

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...