For many years Rose has been assisting her missionary brother in the heart of the African Jungle. When he dies suddenly, she enlists Charlie, a gin-swigging rough-and-tumble river-boat captain, to ship her back to civilization. Along the way they must traverse deadly rapids, disease-infected hoards of mosquitoes, German soldiers, and a river that is not meant for the sturdiest of boats, never mind the old, rickety African Queen.