Tom Swift's father, Barton Swift, is a great inventor with many patents and project sold to both private enterprises and the Government. Now, Tom joins him as they set out to test a new deep diving submarine Barton has build to try to secure a military contract. Driven by a radically new form of propulsion, it is up against other submarines, but their primary opponent is an unscrupulous man who will do everything possible-including attacking the Swifts-to win that contract. Things take a turn when a gold-laden ship sinks off the coast of South America, and it becomes a race both in distance and diving ability to see which submarine will win the contract and also get that gold