Investigating the disappearance of a robot probe, Stingray is drawn to the bottom of a volcano where two survivors of a destroyed city attempt to steal Stingray to escape the erupting volcano. When Marina locks the hatch they are forced to return for Troy and Phones who have been left to die. Since there are only two sets of breathing gear, Troy and Phones must rely on their WASP training to make the swim to Stingray.

After recovering a giant oyster, two explorers are captured by Troy in restricted waters. They persuade Commander Shore to let the Stingray crew help them collect it's pearl. However, the crew are unaware of their real intentions !!

Atlanta is captured by an undersea race when Stingray investigates the collapse of an oil drilling rig. She discovers that the creatures only attacked the rig out of self-defence, believing that their home was under attack. Unfortunately, a bomb has been planted aboard Stingray that will explode when the ship dives. Atlanta makes a desperate effort to contact Stingray but, fortunately, Marina's pet seal, Oink, discovers the bomb and pushes it off in time