'Jumbo' Johnson hires Steve Singleton (and his boat, the "Seeker") to search for pearls on the coast of New Guinea. Johnson tricks Singleton, however, by supplying him with phony permits. Singleton loses his boat and is sentenced to jail. When released, Singleton teams up with boat-owners Daubrey and Sykes to find a downed plane and its cargo of gold bullion. While searching, they rescue one of the plane's passengers, Katherine Shelley, who's been captured by headhunters. Johnson now appears on the scene. Shelley guides him, Singleton, and the others to the underwater crash site. The gold is removed from the plane and now various schemes emerge as each man tries to gain control of it.