It takes a while for the viewer to catch on, but the 1942 quickie Spy Ship is a remake of the 1934 crime melodrama Fog Over Frisco. The main difference is that the film's principal murder victim, the sister of the heroine, is transformed from a dizzy socialite to an out-and-out villainess. The story is re-set during the months before America's entry into WW2. Famed aviatrix Pamela Mitchell (Irene Manning), a devout and outspoken isolationist, is secretly in the employ of the German government. Her younger sister Sue (Maris Wrixon) worries about the company Pamela keeps, and expresses these concerns to hotshot reporter Ward Prescott (Craig Stevens). When Pamela is killed by her Nazi confreres to keep her from revealing all to the world, Sue finds herself among the suspects. It all comes to an end on the spy ship of the title, where a kidnapped Sue is rescued in the nick of time by Ward and practically every cop in New York.
~ Hal Erickson, All Movie Guide