In the land of Hoenn, a girl named May travels to Prof. Birch’s lab. She is attacked by a wild ghost Pokémon called Duskull. Scared, but unharmed, she travels on her bike to the lab in Littleroot Town.
Ash also travels to Littleroot town and is going to sign up for the Hoenn League. Team Rocket's failed attempt to catch Pikachu has left the little yellow Pokémon dangerously ill. Jessie is feeling somewhat depressed, as she does not have any motive to hunt Ash's Pikachu. Ash arrives in town to discover that Littleroot does not have a Pokémon Center! Ash rushes to the nearest telephone booth and talks to one of the assistants. The assistant alerts Prof. Birch. Professor Birch thinks that Pikachu can be cured—but first they'll have to catch it, as it escaped from Ash's hands. Delirious with fever, Pikachu has run off into the forest.
Meanwhile, May arrives at the lab in order to receive her first Pokémon to find that the Prof. is not there. The assistants tell her that he drove into the woods and she rides after them. In the woods, while Professor Birch was searching for Pikachu, he tumbles down a cliff and lands on a Pochyena. He is suddenly surrounded by a group of the Pokémon and he looks like he is in trouble. Suddenly, May arrives and the prof. tells her to take one of the Pokémon out of his bag and use it to battle the Pochyena. She ends up throwing Mudkip. Birch tells Mudkip to do a water gun attack. However, Mudkip attacks May instead of Pochyena.
Ash finds Pikachu, but Pikachu thinks (because of the disease) that Ash is his enemy, so he attacks him. Pikachu flees, and falls down the cliff, but Ash catches him while holding onto a tree in the cliff. Pikachu bites Ash, but Ash still climbs, as May and Prof. Birch arrived with the rope. Pikachu isn't confused anymore, and begins licking Ash's wound. As the group is about to leave, Team Rocket arrive on the scene in a giant robot. They reintroduce themselves to Ash and let May and the prof. know who they are. Jessie still does not care about this mission and James and Meowth do the dirty work as they launch an arm that grabs Pikachu.
Struggling to get free, he lets loose a super-powered Thunderbolt. Since the robot was designed to absorb Pikachu's electricity, it has no effect. Nevertheless, Pikachu continues to unload high-powered Thunderbolts, using up all of his stored electricity. One of the electrical surges destroys May's bike, unfortunately enough. The robot, however, was not designed to absorb this amount electricity, and so it overloads and explodes, sending Team Rocket blasting off for the first time in the Hoenn Region. Jessie, however, realizes that they are hunting Pikachu for their boss, Giovanni.
Back at the lab, Prof. Birch and his assistant perform some tests on Pikachu, to see if he is okay. May comes, asking about Pikachu, then decides to pick her first Pokémon. May picks the Fire Pokémon, Torchic, as Mudkip attacked her, Treecko finds disgusting and Torchic has impressed May already. Prof. Birch gives her a Pokédex and she quietly says how she really doesn’t like Pokémon, but corrects herself in time. The next morning, she goes to room where Ash and Pikachu slept and sees them sleeping. May’s damaged bike due to Pikachu’s thunderbolt makes her angry but she decides to ask Ash if she can go with him on his journey. He says ok and they head over to Oldale town as Ash’s journey in Hoenn begins.
To denounce the evils of truth and love, to extend our reach to the stars above. Jessie. James. Team Rocket blasts off at the speed of light. Surrender now or prepare for an out of this world fight. Meowth, that's right!
Pikachu, where's all your Thunder Bolt?! Well I for one have been doing my homework now dig this! I've come up with a machine that'll beat that pesky Pikachu at its own nasty game. No matter how high these volts go this machine will absorb them!
"That's a water type." "Correct." "Yeah but that Mudkip wouldn't do a single thing that I asked it to do." "Really? How could that little guy cause trouble?" You're very fond of Pokémon aren't you Ash?
Ughhh walking all that way alone makes me nervous and my bike's destroyed thanks to your Pikachu, Mister. There must be a solution, a way to get to Oladale Town safely on foot. Heyyyyy why don't we go there together? I happen to know the way there. Really Ash I don't mind at all. It's no trouble! Shall we?
So with Pikachu fully recovered, Ash and May can begin their journey together. As they head for Oldale Town and the nearest Pokémon Center. Together they're sure to discover new Pokémon and new friends as well. One things for sure, even more adventures lie just ahead.