In the South Seas, Bill Jones, captain of the schooner "Marigold", is known as Captain Calamity as he is quick to fight or frolic. Stone broke on the island of Quica and with his ship in need or re-stocking, Bill accepts an ancient Spanish doubloon from a young Australian named Carr in exchange for taking him to Tapillo, where Carr can take a ship to Sydney. Bill gives the doubloon to trader Joblin for supplies, and does not bother to correct the trader's impression that he has found a fabulous horde of pirate gold. With Madame Gruen, a slatternly jade who runs a waterfront boarding house, and Samson, her oily paramour, Joblin schemes to seize Captain Bill's supposed treasure trove. Together, they gather a a crew of cutthroats, led by Black Pierre, leader of the scum of the waterfront dives, to seize the treasure. Bill also meets Dr. Kelkey, loser in many bouts with a brandy bottle, and his ward, Madge Lewis, on a mission to find the man who murdered and robbed her father in Australia. Bill agrees to help her, but does not remember her as the young girl he had saved from a sinking ship a dozen years before.