Sealed Cargo was based on The Gaunt Woman, a novel by Edmund Gilligan. Dana Andrews stars as Pat Bannon, a Newfoundland fishing-boat captain during WW II. Coming to the rescue of an endangered vessel, Bannon finds himself in the middle of a nest of Nazi spies. Reasoning that he'll never be able to alert the authorities, Bannon takes it upon himself to scuttle an impending large-scale German submarine attack. Claude Rains is the personification of cultured evil as the head Nazi naval officer, while Carla Balenda co-stars as an innocent bystander who may well lose her life as a result of Bannon's planned heroics. Sealed Cargo was one of several moneymaking films released by RKO Radio during one of the studio's most profitable years.
by Hal Erickson synopsis