A vivacious young woman known only as Captain Joe captains a rum-runner operating between the Bahamas and the United States. Jerry Burke, a Secret Service agent assigned to the Bahamas to halt this illegal trade in rum, meets Captain Joe, whom he knows as Peggy O'Day, and falls in love with her, arousing the antipathy of Pietro, Peggy's first mate. Pietro later learns that Jerry is a government agent and kidnaps him, hiding him on Peggy's boat. Making a delivery to the mainland, the boat is then attacked by hijackers led by Pietro, who wound Peggy and take her boat, leaving behind Jerry and Peggy. Taking the hijackers' craft to a small island, Jerry sends a radio message for help to Peggy's father, a cashiered naval officer; Pietro intercepts the radio message, goes to the island, and forces Peggy and Jerry aboard the rum-runner. Peggy manages to send an S. O. S. signal to a U. S. warship before Pietro dynamites the boat. Peggy and Jerry survive the explosion and are picked up by a Navy warship; Pietro is captured, and Jerry uses his influence to have the elder O'Day cleared of the false charges that led to his disgrace. Peggy and Jerry make plans to be wed.