Commander Dumax and his army of praying manti (who look exactly like Space Ghost's sidekick Zorak) have come to invade Earth. The Neptune's, on their way to Hydrostan, hear of a UFO sighting in the area ,and Biff decides to use this as a publicity stunt. Unfortunately, Clamhead and Jabberjaw are pursued by the aliens, the stunt backfires. In the meantime, Dumax gets an Earth identification device, which will help with his plans. The Neptune's are taken prisoner by Dumax but escape and must thwart his invasion plans.
Uma espaçonave extraterrestre chega a Terra sob o comando do alienígena Dumax, com a missão de conquistar o planeta. O primeiro território a ser dominado é a cidade subaquática Hydrostan, onde o grupo Netuno, de Tutubarão e sua turma irá se apresentar mas, não sem antes confrontar-se com os inconvenientes visitantes.
Die Neptunes geraten durch ein Versehen in das Visier Außerirdischer. Diese wollen die Welt erobern. Sie werden von den Außerirdischen mit einer Rakete ins All geschossen. Doch die Aliens haben nicht mit Sharky gerechnet.
