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.