Sixth sense tells Dominie d'Arielle, an orphaned and wealthy 1840s Parisian miss, that her brother Denis, a Jesuit priest, courts danger by spreading Catholicism in Vietnam. When her elderly fiance refuses to honeymoon with her in the Orient, Dominie packs some diamonds, disguises herself as a nun and heads off alone to save Denis. En route, she falls into the hands of a white slaver and is retrieved from his clutches by some sailors who are on shore; but mistaking Dominie, who has shed her nun's garb, for a prostitute, they turn her over to Capt. Jared Barron for his amusement. Jared is heading to China in search of his own brother, Matthew, who has rashly entangled the Barron family fleet in the opium trade.