An ill-conceived attempt to turn himself invisible renders Admiral Bubbles green and glowing. Beanie takes him to a veterinarian who announces that he needs to be kept for overnight. Despite Beanie’s protests, Admiral Bubbles is left locked up in the lab overnight where he concocts a potent Fishy-Pox virus that will turn any infected human into a water breather. He soon infects part of the population, spraying the germs from a water truck as he passes helpless citizens. As Beanie and Elwood try to track down the fish, two renegade security guards also hunt for Admiral Bubbles: they want to capture the goldfish and sell him to the army as a secret weapon! Beanie soon becomes infected, but realizes that the additional dose he received caused the virus to start attacking itself, rendering it harmless. With the goldfish locked up in the hands of the guards, Elwood and Beanie make an antidote and pour it into the town water supply, where it reverts the population back to normal. They rescue Admiral Bubbles who discovers that his Fishy-Pox has turned into a common cold.