Josh, der sonst immer Herr der Situation ist, blamiert sich vor den anderen Schülern, als es darum geht, eine neuartige Schwimmhilfe zu testen. Er hat offensichtlich Angst vor Wasser. Schon bei der nächsten Mission stellt sich das als großes Problem heraus: Eine Gruppe von Banditen entzieht Planeten ihre Wasservorräte. Die Übeltäter können allerdings nur unter erschwerten Bedingungen gestellt werden, nämlich unter Wasser. Als Josh sich weigert, müssen Brett und Yoko alleine eingreifen...
When Galaxy High receives distress signals from various planets in the universe, Principal K sends several teams out to investigate. When they arrive at their various destinations, they uncover that the planets are not only abandoned, but completely dried out – what were once fertile, colorful worlds are now dusty and desolate. But before the teams can investigate further, Kirkpatrick informs them that yet another planet has sent out a distress call. Josh’s team springs into action, heading toward the planet in their Hornet. When they arrive, they are shocked to discover the planet being drained of its water supply by a large alien ship! The marshals try to stop the plundering, but they are unable to—the ship is too fast and gets away. The GH students ultimately trace the ship back to its H2O-covered home planet where they discover a race of aquatic aliens who are using the stolen water to replenish their own planet’s supply. They must journey under the water (using a cool, new GH gadget) to battle the aliens. In a b-story, Josh tries to hide his inability to swim
