In the last episode, Clark and professor Thorpe have rescued the real Captain Maddox, exposed the fake captain, and have recieved a strange radio message. The voice belongs to a man named Escobar. A man who the captain recognizes as a pirate.
A meeting has been arranged with Escobar, and Clark poses as a deep sea diver who wants to join the pirate gang. When the pirate gang sees through the ruse, Clark springs into action as the Man of Steel to get himself and captain Maddox to safety. The trip revealed the pirate mission, to use the bathosphere to bring up sunken gold.
Professor Thorpe admits that it was his secret as well since he put all his money into building his bathosphere. He wants the gold to build the ultimate scientific labrotory.