The film tells the story of missionary Nathaniel "Nate" Williamson, taken to an island mission with his fiancée Sophie. Their ship, the ''Rona'', is captained by the roguish William "Bully" Hayes, who also takes a liking to Sophie. When Sophie is kidnapped by slave trader Ben Pease, "Nate" teams with Hayes in order to find her. The two men enjoy a friendly rivalry for Sophie's affections, and she is to some extent torn between them, though committed to Nate.