A nazi-spy-ring in the USA attempts to steal a new formula for synthetical rubber while sabotaging the US-weapons. A police officer goes undercover and is - for his credebility - fired by the police. When his only superior who knew of his mission is killed he has to go on by himself. He succeeds in joining the spy-ring while at the same time fighting them as a masked superhero. At the end he manages to decrypt the key used by the nazis to encode all their communication and he is able to pass these new pieces of information on to the government which is then able to destroy the spy-ring.