 A certain pirate of the Spanish Main makes a practice of blowing up with all hands the ships he has looted. By a fluke, one man and his dying father survive such a disaster. Swearing vengeance, the son joins the pirates; soon, "the black pirate" swashbuckles his way into their black hearts, capturing a merchantman singlehanded. Can he now save the life of lovely Isobel? Can he, opposed by a treacherous rival, rise to lead the pirates and thereby deliver them to justice?