Now on their way to Ecruteak City, Ash, Misty, and Brock, arrive at the National Park to find that the Bug Catching Tournament is behind held today. Ash asks the man in front, who dressed as a Venomoth, if there's some sort of prize involved. He tells him that the winner gets a Sun Stone as well as whatever Bug Pokémon he captures along the way. With that in mind, Ash decides to join in.
In the registration line, Ash's old friend, Casey, spots the gang. She runs over to greet our heroes, and Brock compliments her Chikorita for looking stronger than ever. Casey tells Ash that since they first met, she's been on a winning streak, just like her favorite baseball team, the Electabuzz. In fact, Casey decides to sing the Electabuzz's new fight song, which freaks everybody out. Ash also discovers that Casey is entering the contest and vice versa, so the two realize that they're going to have a little competition. Meanwhile, Team Rocket is shocked to find out that they can't take part in the Bug Catching Tourney, since only people under 16 can compete. Jessie and James then disguise themselves in school uniforms, posing as 12 and 13 year olds. However, the Venomoth man doesn't fall for the false getup, and refuses admittance. Annoyed, Jessie has the man taken away with a snap of her fingers. She then asks herself if she really looks older than 16, and gets upset when no one responds. James and Meowth try to calm her down, reassuring that she looks just like a big baby. They soon find out that that was the wrong thing to say.
The rules are explained to the contestants. They can only use one Pokémon, and they'll have to use a Park Ball to capture whatever they find. When time runs out, a winner will be declared, at which time he or she will receive the Sun Stone. The contest begins, and everyone scatters. Watching the contest from a big screen in the stands, Misty wonders if there could be any bugs in the trees nearby. Brock assures her that there probably are. As Ash finds a Weedle, the screen gets a close-up of it. Misty is terrified, crying out why the screen has to be high definition. Pikachu prepares to attack the Weedle, but Casey's Chikorita jumps in and uses Razor Leaf, allowing her to capture it first. Ash yells at Casey for stealing his catch, but Casey begins to talk about how the Electabuzz take every chance they get to steal home and that she always swings for the fences. Confused, Ash just tells her that he doesn't speak "baseball". Now hiding behind the tree behind Brock, Misty asks what's happening. Brock tells her that she should watch the contest herself, but Misty refuses to come out. Seeing her Togepi playing with a Caterpie, Misty frantically swings at the Bug Pokémon with her bag to make it go away. Next, a Spinarak comes out from the tree, so Misty swings at it too, nearly hitting Brock.
In another part of the park, Jessie stands dressed as a Venomoth. She asks James why she has to the bait, and he mentions it's because she's so alluring. Realizing that he's right, Jessie goes into a fantasy-like daydream, telling herself that no species can resist her. A real Venomoth approaches. Jessie tries to seduce it, but the Venomoth quickly speeds away, leaving a trail of Stun Spore behind. Team Rocket collapses and decides to go with plan "B". Making her way through a small forest, Casey orders her Chikorita tackle a tree. A group of Pineco drop, and while Chikorita is busy battling, Ash tells Casey that Pineco have an advantage over Grass types. Casey says that she already knows that, and walks away. Exhausted, Chikorita follows its trainer. Watching what's going on, Misty notices that if Casey keeps her pace up, Ash won't have the slightest chance of winning. Misty then admits that even though she hates Bug types, she wishes for Ash to catch at least one.
Casey finds a lone Scyther not too far away. Knowing that capturing a Scyther would be a near-definite win, she tells Chikorita to use Razor Leaf. Scyther retaliates by lunging itself at Chikorita, severely hurting it. Casey commands Chikorita to use Razor Leaf again, but Scyther deflects the shots back at its opponent. Too weak to continue, Chikorita desperately jumps onto Scyther's face, preventing it from seeing as it frantically slashes around. Ash arrives at the scene and tells Casey that what she's doing to her Chikorita isn't fair. Suddenly, Chikorita is slammed into a tree, and Scyther moves in for the finishing blow. Pikachu shocks Scyther and runs with Ash, providing as a distraction to save Chikorita. Misty notices that her Togepi is missing, when she spots it on the big screen wandering around the park. She enters the park and finds Togepi together with Casey's Chikorita, who apparently does not want to be found. Casey appears, and Misty scolds her for pushing Chikorita too hard. Realizing that she's been too busy thinking about winning instead of the well-being of her Pokémon, Casey begins to regret everything that she has done. Chikorita comes out from hiding, approaches its trainer, and forgives her. As the two make up, a Paras drops on Brock's back. Misty violently swings at it, hitting anyone that comes near.
Hiding behind a bush, Ash finds a horde of Beedrill buzzing overhead. Ash throws the Park Ball at one of the Beedrill, but it doesn't work. Realizing that he has to weaken it first, Ash uses Pikachu to use Thunderbolt. Afterward, Ash tries the Park Ball again, and is successful this time. As Ash and Pikachu are celebrating the capture of their new Pokémon, they fall into a hole. Ash figures that this is another one of Team Rocket's lame traps, but suddenly a large cage comes from above and pulls the two up. As usual, Team Rocket makes their dramatic appearance. Pikachu tries to shock the cage, but ends up shocking Ash instead. Casey, Misty, and Brock come to the rescue. Team Rocket remembers Casey as the "pep squad girl from the Electabuzz losers". Casey tells Team Rocket that they know nothing about baseball, and Meowth comes to the conclusion that she's right. Ash tells Casey to run away, but she refuses. Casey orders Chikorita to use Razor Leaf, but a giant net catches all the leaves. James laughs, saying, "We made the catch!" Jessie is distraught, realizing that they're going to have to start using baseball terms. Meowth pushes a button, and a baseball-shaped missile aims for the gang. As Casey tells Chikorita to get ready, it suddenly evolves into a Bayleef. The missile fires. Bayleef unleashes a volley of Razor Leaves at it, destroying the missile before reaching its target. It also breaks the cage imprisoning Ash and Pikachu. Pikachu finishes Team Rocket with a Thunderbolt, and they blast off… again.
Later that day, the winner of the Bug Catching Tournament is declared. Ash's Beedrill ends up getting him first place, as well as the Sun Stone. Outside, Casey congratulates Ash for a well-deserved victory. Ash tells Casey that since she helped him escape from Team Rocket and because he knows she loves yellow striped Pokémon, she can have his Beedrill. Casey almost begins to cry as she thanks Ash for the gift, and in return, treats him to the Electabuzz's fight song. And just as the episode draws to a close, Casey tells us to not forget to root for the Electabuzz!