Ash and co. are still on their way to Violet City. Today, they have stopped at a town called Cherrygrove City. It's a perfect day outside. Brock is cooking some lunch while Ash is cleaning is Pokéballs. His Pokéballs shine in the bright sun. Pikachu hands Ash the GS Ball to clean next. Misty notices that Ash has been acting like a more responsible trainer. Ash tells her that cleaning Pokéballs is quite important. Brock calls everyone down for lunch. Ash and Misty hurry down to Brock. Pikachu is also about go when it sees something in the water. Ash sees it too. It's a Quagsire. Ash looks up Quagsire in his Pokédex. Misty finds Quagsire to be a cute water Pokémon. She wants to capture it. Before she can throw a Pokéball, Psyduck pops out. Quagsire and Psyduck just stare at each other. When Misty moves Psyduck out of the way, Quagsire quickly grabs the GS Ball and swims away. Ash chases Quagsire. He sends out Squirtle to retrieve the GS Ball. Squirtle swims up to Quagsire and jumps on top of its body. Because of Quagsire's slick skin, Squirtle falls off. Ash asks Squirtle if it is still okay. Squirtle keeps on going, but Quagsire whacks it with its tail. Squirtle gets back up again and uses Water Gun, causing Quagsire to drop the GS Ball. Pikachu catches it. Then Quagsire uses its own Water Gun and the two water attacks collide against each other. Misty holds up a Pokéball to capture Quagsire. Suddenly, they hear a whistle blow which came from Officer Jenny. Officer Jenny tells them that they are under arrest.

At the police station, Professor Oak, who is on the phone, tells Officer Jenny to free Ash and co. Officer Jenny tells him that she will let them go. Then she says that Quagsire battling and catching is not allowed. Many people in Cherrygrove City like the Quagsire a lot. Professor Oak tells Ash and co. to not get in trouble again. Brock says that he won't let them cause trouble. Brock holds Officer Jenny's hand and tells her that he won't cause her any trouble. Officer Jenny thinks that Brock is a bit weird. Then Misty pulls him away. Ash wonders why the Quagsire tried to steal the GS Ball. Officer Jenny tells him that it's because the GS Ball is round. Every year, the Quagsire comes to town to take round things, and then they perform a little ceremony with the round things. The Quagsire float upstream with the round objects, and then by the next day the objects come floating downstream. People are happy that their things are taken because when they get their things back, good luck is brought to them especially if your objects is the last one to come. Ash and co. then sees the same Quagsire tapping on the window. Ash tells Quagsire that it is not getting the GS Ball.

Outside, Ash and co. are starving since they never ate lunch. They see a different Quagsire take a round object from a bridge. Ash and co. finds it weird on how Quagsire only take round objects. The same Quagsire appears next to them. It wants the GS Ball again. When Ash tells Quagsire that it cannot have it, Quagsire throws itself on Ash's body. Misty and Brock try to get Quagsire off, but its slippery body prevents them from doing so. Ash drops a Pokéball and Chikorita comes out. It sees this and spins the leaf on its head causing everyone to fall. Brock thinks that Chikorita might have a "crush" on Ash. Just then, the GS Ball falls out of Ash's backpack. Quagsire quickly grabs it and swims away. Ash falls over with Chikorita right next to him. Brock thinks that Chikorita is getting a bit crazy now.

Team Rocket is also in Cherrygrove City. Meowth is holding a shiny round ball. Jessie is frustrated that they lost Ash and co. again. James is looking at a map. Jessie asks Meowth where he found the ball. Meowth tells her that he found it in a field. James pretends that he is a gypsy and uses the ball to find Ash and co. Before he can see a vision, a Quagsire appears and steals the ball. Jessie is mad by this. She decides to use Arbok and Lickitung for battle. Before she can send the Pokémon out, some other Quagsire steals her Pokéballs. James' Pokéballs are stolen by Quagsire too. They decide to chase the Quagsire down.

Ash and co. tries to catch up with Quagsire, but they have lost track of it. Brock suggests that they wait for the GS Ball tomorrow because it would just float back down. Suddenly, four Quagsire are seen swimming in the water. Ash and co. decides to follow them hoping that they will lead them upstream. Team Rocket are also running in the same direction. Meowth thinks that it heard Ash and co. James says that they can't catch them until they have their Pokémon back. So they continue to run. Ash and co. peer behind tall grass. They see all the Quagsire with round objects in the water. Brock says that the place is called Blue Moon Falls, but he doesn't see any waterfalls. Ash agrees with him. Then he sees the Quagsire with the GS Ball. Ash stands up and wants to capture it, but Misty reminds him that they are not allowed to capture or mess around with the Quagsire. Brock tells Ash that they will keep their eye on Quagsire incase it tries to get away. Team Rocket is also in the same area where Ash and co. are. Meowth suggests that they quickly grab Pikachu. Jessie tells James and Meowth that they should capture the whole herd of Quagsire. Meowth likes Jessie's plan. James wants to stay behind, but Jessie tells him to not be a coward.

Ash and co. now notice that the Quagsire are all standing up. They wonder if the Quagsire are waiting for something. Suddenly, from the sky, Team Rocket comes down and steals one of the Quagsire. Then they say their motto. During the motto, the Quagsire slips away. This gets Team Rocket angry. They try to grab onto more Quagsire, but they too all slip away. When Team Rocket realizes that they cannot capture the Quagsire that way, they move to Plan B. A net springs down from the balloon, capturing all the Quagsire in it. James wonders where the Quagsire put all of their Pokéballs. Team Rocket's Pokéballs are still on the ground. Team Rocket uses their mechanical claws to get their Pokéballs. Ash calls out for Team Rocket to let the Quagsire go. Team Rocket tells Ash that they are also going to grab Pikachu. The mechanical claws grabs onto Pikachu. Some other Quagsire from the grass throws rocks at Team Rocket which frees Pikachu. Then Ash sends out Bulbasaur. Bulbasaur uses Razor Leaf which breaks the net. The Quagsire all fall into the water. A final rock is blasted into the balloon, and Team Rocket blasts off again.

The Quagsire continues their ritual. They all begin to head upstream together. Ash and co. decides to follow them. The Quagsire are now in a different area. A blue moon lights up the sky and a waterfall is present. Misty wonders what the Quagsire are going to do with the round objects. Brock tells her to watch and find out. The Quagsire all use their Water Gun to shoot the objects over the waterfall and down to the other side. Brock thinks that it might be a competition on which object can get closer to the moon. Then they notice the sparkles in the sky. Then the Quagsire with the GS Ball approaches them. It throws the GS Ball up and blasts it with a Water Gun. The GS Ball went higher than the rest of the objects. The Quagsire cheer. Ash notices that the GS Ball is getting away, and so him and his friends chase after it.

The next day, everyone gets their objects back. Officer Jenny directs the people to the exit. The last item approaches. It is the GS Ball! Everyone wonders who it might belong to. Ash calls out telling everyone that the GS Ball belongs to him. Officer Jenny picks it up and hands it over to Ash. She tells Ash that he will have the best luck ever because it was the last item to come down. Everyone claps for Ash and his GS Ball. Ash is happy. To him, he is the winner of the Johto League. He thinks that he is unbeatable and can never lose.

English Official Summary

Professor Oak's errand—to deliver the mysterious GS Ball to a Poké Ball expert—is interrupted when a Quagsire with a penchant for spherical objects steals the GS ball for use in a nocturnal ritual.

Italian Official Summary

La missione, affidata ad Ash dal Professor Oak di consegnare la misteriosa GS Ball a un esperto di Poké Ball, viene messa a repentaglio quando un Quagsire con un debole per gli oggetti sferici ruba la GS Ball…

Portuguese Official Summary

A tarefa do Professor Carvalho de entregar a misteriosa bola GS para um expert em Poké Bolas é interrompida quando um Quagsire fascinado por objetos redondos rouba a bola GS para um ritual noturno…

Spanish Latin America Official Summary

El encargo del Profesor Oak de entregar la misteriosa Bola GS a un experto en Pokébolas es interrumpido cuando un Quagsire que gusta de los objetos redondos roba la Bola GS para un ritual nocturno…

Spanish Official Summary

El recado del Profesor Oak de entregar la misteriosa GS Ball a un experto en Poké Balls, se ve interrumpido cuando un Quagsire con una inclinación por los objetos esféricos roba la GS Ball para usarla en un ritual nocturno.

English Great Britian Official Summary

Professor Oak's errand—to deliver the mysterious GS Ball to a Poké Ball expert—is interrupted when a Quagsire with a penchant for spherical objects steals the GS ball for use in a nocturnal ritual.

Dutch Official Summary

Professor Oak’s opdracht om de mysterieuze GS Bal naar een Poké Bal expert te brengen, wordt onderbroken als een Quagsire, die dol is op ronde voorwerpen, de GS Bal steelt voor een nachtelijk ritueel…

French Official Summary

La mission du Professeur Chen, qui consistait à remettre la mystérieuse GS Ball à un expert en Poké Balls, est compromise lorsqu'un Maraistre ayant un penchant pour les objets sphériques vole la GS Ball pour l'utiliser pendant un rituel nocturne.

German Official Summary

Professor Eichs Aufgabe – den geheimnisvollen GS-Ball zu einem Pokéball-Experten zu bringen – wird jäh unterbrochen, als ein Morlord mit einer Vorliebe für runde Dinge den GS-Ball für ein nächtliches Ritual stiehlt.