While heading to the first stop on their journey, Pikachu was captured by Team Rocket and Ash and co. were not far behind. After their balloon popped Team Rocket found Pikachu protected by a Turtwig. When Ash and co. found Pikachu with Turtwig it's caretaker, a kindly old lady by the name of Clara, invited them over for lunch. Turns out she's a Pokémon caretaker and Turtwig (Like Bulbasaur before it) is her bodyguard but it really likes Ash. Will Ash accept Turtwig?
Ash, Brock and Dawn chase Team Rocket for, yet another, attempt to steal Pikachu. So, Ash sends Starly, who goes to use Wing Attack to cut the rope Pikachu's cage is attached to. James sends Carnivine, who bites him on his head. This causes the balloon to shake and, by accident, Starly pierces the balloon and the balloon falls down. Team Rocket lands down near a lake and a Turtwig sees all this. Turtwig opens Pikachu's cage, setting him free. Team Rocket did not give up to get Pikachu, even if Meowth translates they are trespassing. Carnivine uses Bullet Seed, but Turtwig evades and tackles it. Carnivine is knocked out on Team Rocket, who got blasted off.
The heroes arrive and see Pikachu safe, and a Turtwig as well. Dawn wants to capture it and sends Piplup. It goes to Peck, but evades the Razor Leaf. The attack damages an nearby Oddish, who uses Sleep Powder. Ash gets Pikachu, but they both fall asleep. Turtwig gets Pikachu and runs away. Brock and Dawn go to chase after it, but an older woman appears. Inside the woman's house, the woman gives Ash a drink and he wakes up. The woman introduces herself as Clara and tells Pikachu is safe with Turtwig. Turtwig and Clara are friends. Turtiwg bashes a tree and offers a fruit to Pikachu, who eats it. Clara says Turtiwg helps everyone. One day, it just appeared, so she gave it food and it never left. The Pokémon around made it their leader.
A Geodude and a Mankey fight for fruit, so Turtiwg bashes the tree and takes away the fruit and soon get into a fight, making Turtwig the winner. Clara tells it is a lot of responsibility for a person to take care of it. Ash goes to tell Turtwig he is Pikachu is owner. Turtiwg gave an equal amount of fruit to Mankey and Geodude, keeping both sides happy. The heroes arrive to get Pikachu, but Ash gets tackled by Turtwig. The heroes explain Team Rocket are the ones who took Pikachu. Pikachu finally persuades Turtwig that Ash is his trainer, so Turtiwg apologizes. Ash is still grateful it took care of Pikachu. Suddenly, they see an injured Linoone. They take it to Clara's house, where Brock uses Clara's herbs to treat Linoone. Team Rocket see all this and prepare themselves to capture Pikachu and Turtwig.
Brock made lunch. Turtwig gives its food to Linoone and Ash now knows Turtwig wants to help around. Ash tells it needs to eat and gives it food, resulting that Turtwig bites Ash's head, though Clara tells it likes him, showing its affection. Turtwig goes to bite Clara's head, but she stops it with a branch. Suddenly, Turtwig and Pikachu are taken by Team Rocket. Both are taken away, so Ash jumps in the lake to get them back. Dawn sends Piplup to assist him. Team Rocket are happy they caught them, but soon Ash and Piplup are spotted - they got on the cage where Turtwig and Pikachu are. Team Rocket dive, so Turtwig begins to tackle the cage. Pikachu uses Iron Tail and Thunderbolt to get himself and Turtiwg out, but in so doing, he wounds Ash, Piplup, Turtwig and Team Rocket. Brock, Clara and Dawn track them and Clara is exhausted. Still, Ash, Piplup, Pikachu and Turtwig are blasted off on the land and everyone is fine.
Turtwig glows and heals itself using Synthesis. Team Rocket did not give up and also go on the land. Jessie sends Seviper and James Carnivine. Seviper uses Poison Tail and Carnivine goes to bite, but Turtwig tackles seviper and bites Carnivine. Carnivine and Seviper repeat their attacks, but they got blasted off, along with Jessie, James and Meowth by Pikachu's Volt Tackle. Turtwig once again bites Ash's head for its affection. Ash, Dawn and Brock leave Clara and Turtwig. Clara knows Turtwig wants to go with them and allows it to do it. Clara tells Ash it wants to come with them, but wants a battle first. Turtwig charges, so Pikachu attacks with Quick Attack. Turtwig uses Razor Leaf, but Pikachu evades. Soon, Turtwig charges again, hitting Pikachu. Although Pikachu evades, Turtwig still bites his tail, so Pikachu tries to wave his tail around to get it loose.
Ash orders Pikachu to go to a nearby tree and Pikachu uses Iron Tail to bash it to that tree and follows with Thunderbolt, paralyzing it. Ash throws his Poké Ball... and captures Turtwig. Ash promises Clara he'll take care of Turtwig and with Brock and Dawn, goes to Jubilife City.