Beanie has long suspected that Mr. E, the mysterious owner of the local pet shop, is a space alien. While helping clean up a mess it is in fact Admiral Bubbles that stumbles upon a hidden room filled with strange otherworldly artifacts, including what appears to be an alien ray gun. When Admiral Bubbles tries to turn the ray on Beanie, an accident results in the goldfish blasting himself with the ray. Admiral Bubbles mutates into a 7-foot-tall monstrous goldfish that stands on two legs. No longer an inconspicuous goldfish, he soon finds himself pursued by the police. He heads toward the city harbor where he will take refuge in the water and plot his attack—but to his horror, he discovers that he can no longer breathe under water, or swim! Soon he has another problem: a mysterious “men in black” style agency is also looking for him. In a race to see who will capture Admiral Bubbles first, Beanie makes use of a strange “Reversotron” from Mr. E’s secret room that transforms Admiral Bubbles back into an ordinary goldfish. Safely back at Mr. E’s pet shop, Beanie discovers that Mr. E has removed all evidence of his secret room, leaving both Beanie and Admiral Bubbles unsure of the identity of their friend.