Episode Title:Deep Search.Episode Description:On Jupiter's moon Europa, the stars of Gordon's favourite explorer program (Buddy and Ellie Pendergast) are searching for extra-terrestrial life. When they begin drilling into the ice, pressure from geysers cause the ice to crack and they plunge into an underground ocean ten miles below. Alan (in command) and Gordon blast off to the rescue in Thunderbird 3, with Thunderbird 4 stored aboard and modified with skis, powerful engines and a heat drill to penetrate the ice, which they lose due to strong underwater currents. They find the Pendergasts, who have taken shelter in their rover, but before they leave they detect a life form in the sea.