Unseen Enemy (1942)

The Unseen Enemy in this wartime meller is Nick Leo Carrillo the outwardly effusive manager of a San Francisco waterfront café To make enough money to ensure his daughter Gens Irene Hervey entree into society Nick sells his services to a gang of foreign spies who then use Nicks establishment as a rendezvous point The plan is to covertly send out a Japanese vessel for the purpose of raiding and destroying American merchant ships The spies secret code is hidden in the lyrics of a song called Lydia which the unwitting Gen performs on request day after day