As our story opens, Clark has been called into Perry Whites office where he meets professor AB Thorpe. The professor is to set sail to the Caribbean Sea to do research in his new bathosphere. Troubling word arrives that the ship, the Juanita, has disappeared from the dock in Key West. Now all the professor’s life work has vanished with it.
Being an old friend of Perry’s, the editor of the Daily Planet lets Clark fly the professor in the company airplane to the dock. When they are met by gunmen, it’s Clarks chance to spring into action as Superman to rescue the unconscious professor Thorpe.
Why did the Captain open fire? Clark suspects that Maddox isn’t trustworthy. Clark also hears a tapping sound coming from the hold of the ship. What does it mean?