Stingray - Season 1 Episode 31 Trapped in the Depths

Atlanta is taken captive by the crazed professor Cordo who rules a race of innocent underwater people. When Stingray arrives at his undersea farm he decoys Troy and Phones into a mock-up of Stingray while his subjects take command of the real craft and head for Marineville. Troy and Phones manage to overpower the professor in time to force him to recall Stingray before the creatures can launch their attack.