This episode documents a deep sea submersible dive to study the lingcod and the six-gill shark. The lingcod are food fish that live in various diverse depths. The marine researchers aboard the submersibles are studying the causes and effects of the depleting lingcod populations, concentrating study on the baby lingcod population, and comparing lingcod baby numbers found in shallower depths to lingcod babies found in deep depths. As for the six-gill sharks, the goal is simply to learn more about them. The six-gill sharks are a relatively newly discovered type of shark that lives deep in the ocean. The equipment used to conduct the dives are the Deep Rover submersible, the Aquarius 2000 submersible and the Newt Suit deep diving suit. The episode is more focused on the process of underwater exploration rather than the findings that resulted from this.