On a treasure hunt in the tropics, adventurer Mortimer Gregg discovers beautiful Horse Island, and upon his return to New York, forms a partnership with Christopher Beaumont, allegedly to develop the island's resources. Just before his death, however, Gregg reveals to his assistant manager, David Smith, that the Tropical Products Company was formed for the sole purpose of swindling the stockholders. A highly principled man who believes in the island's potential, David refuses to tamper with the company's financial reports, which so angers Beaumont that he visits Horse Island to deliver David an ultimatum. When the young man learns that he is about to be fired for his persistent honesty, he refuses to allow Beaumont and his daughter Christabel to leave the island. Caught in a tropical storm one afternoon, David and Christabel take refuge in a cave, where they fall in love and, incidentally, uncover a store of pirates' gold. After the Beaumonts have departed for New York, David invests the treasure in Tropical Products stock under Christabel's name, whereupon old Beaumont, finally beaten, agrees to run the company honestly as the partner of his future son-in-law.—AFI