In outer space, five planets adhere to each other, and in Filburt's trailer home, the turtle wakes up and breaks out into a rash.
At Rocko's house, Rocko and Heffer are making Filburt's birthday cake for him on his 21st birthday. Little do they know, Filburt spends the day at his home scratching until a blemish sprouts on the top of his head. As Filburt arrives at Rocko's house, Rocko and Heffer surprise him, and Filburt stares at the high towered cake smothered with Teriyaki Sauce. He goes hysterical and claws at the cake. He sees the cake as Kerplopitgoes Island, the place where he was born in. When a storm precipitates, Filburt explains to Rocko and Heffer that every turtle must return to their birthplace in order to reach adulthood by the time they turn 21, which Filburt wants to avoid. He tells his two friends to make sure he is inhibited to leave the house.
Later, Rocko and Heffer get a call from the wild for Filburt. When Filburt receives the call, he hears the sound of the cohesive planets from outer space and quickly hangs up the phone out of shock. He attempts to leave the house to get his water slides, only to get held back by his friends. He wears a disguise of Rocko while the latter is in the kitchen and attempts to drive away, but is caught again by Rocko and Heffer, who finally lock him up in a cage to keep him from escaping while the two run errands. Filburt gets Spunky to help him escape so the former could get to his hometown.
Later, at the Nifty Drug Store, Rocko and Heffer watch a television of the news reporter informing that a turtle (Filburt) hijacked a ship. Rocko and Heffer return to Rocko's house to discover that Filburt has escaped. So the two travel to Kerplopitgoes Island on a quest to find their friend. They come across 'Club Spawn,' a party of turtles, and find Filburt (who everyone knows as Steve). Rocko tells "Steve" that he and Heffer have come to rescue him, but the turtle refuses to go, claiming that he finally gained the wonderful life as an adult. Knowing that there is nothing that they could do to change the turtle's mind, Rocko and Heffer sadly leave the club. Suddenly, the planets in outer space disperse, and another storm pours down on the island, prompting the turtles to leave. Filburt reunites with his friends as they head home.
At Rocko's house, the news reporter informs that the Jolly Robert's seafood restaurant was returned in its place in O-Town arena. Rocko tells Filburt that he is glad that he is back, and Filburt realizes that being an adult isn't bad after all right before apologizing for going crazy. Rocko accepts Filburt's apology, saying that "nature's own makes us a little crazy at times." Just then, four restaurants are seen adhering to each other, and back in Rocko's house, Heffer breaks out in a rash, uttering out a loud "moo" in the process.