Chikorita's Big Upset (Japanese: チコリータはごきげんななめ！？ Chikorita's Jealousy) is the 20th episode of Pokémon: The Johto Journeys.
On their way to Azalea Town Ash has a battle with a local trainer in a new town. During the battle Ash recalls Chikorita for Pikachu but Chikorita refuses. The battle was called off on account of it getting late. At the Pokémon Center Ash wonders why Chikorita didn't want to be recalled, and after a thorough psychological analysis, the Nurse Joy reveals that Chikorita is jealous of Pikachu because Chikorita thinks Ash likes Pikachu more than her. Later that night Chikorita runs away and joins a gang of fighting-type Pokémon. Will Ash ever see Chikorita again? And will Chikorita get over its jealousy?
Ash battles using Chikorita against a school boy's Raticate. Chikorita goes to use Tackle, but gets hit by Hyper Fang, then by Quick Attack. Ash goes to call her back, but Chikorita disobeys and retaliates using Razor Leaf. Ash is glad she attacked, but tells he is going to replace her with Pikachu, causing her to run away. Since the night came, the boy goes to the house, as he has not got all day. Ash tells Chikorita they would've won if she listened, so puts her back in the Poké Ball. At the Center, Ash contacts Oak, telling him he won the Zephyr Badge already. Oak remarks that, but reminds him he needs to deliver the GS Ball, then gets hugged by Muk. With that done, Oak logs out.
Ash goes to see the Pokémon, who all eat, except Chikorita. Pikachu comes and offers her food, to which she refuses by bashing it with her leaf. Joy comes, who tells that Pokémon behave in different ways, so she studied psychology to understand their behavior. She tells she provides new Pokémon therapy, making Ash confused as she might have discovered a new Pokémon named Therapy. Misty lets him know it is a technique to help with psychological problems. Brock flirts with her, telling that he has problems and thinks she might find it more interesting than Pokémon's, but gets his ear pulled by Misty's hand. Joy proposes to Ash to join the Counsel to see what is wrong with Chikorita. Ash explaines that he wanted to switch Chikorita after it got worn out with Pikachu. Joy heard the last part and sees Chikorita is suffering from envy, she is jealous of Pikachu (making Brock upset why do not they talk about his jealousy). Ash wonders why would she feel that way, since he gives her plenty of attention. Joy clarifies Chikorita thinks he pays more attention to Pikachu than to her.
Fortunately, Joy knows how to deal with that, so brings them all to an arboretum, where she can feel comfortable. Brock admits Joy is his type, causing him to be pulled by Misty. Ash calls Chikorita in the Poké Ball (per Joy's advice), but wonders if the therapy will help. Joy is confident it will work and takes his Poké Ball for Chikorita to rest in the greenhouse for the night. At the night, Pikachu wakes up and sees Chikoita's Ball moving in the greenhouse. Chikorita comes out and goes out of the greenhouse. Pikachu tries to reason with her, but almost gets hit by Razor Leaf, as Chikorita runs away. Pikachu tries to find her, as Chikorita ran to an abandoned warehouse, where she finds a place to sleep.
Chikorita wakes up and sees a Machoke, a Hitmonlee, a Hitmonchan and Primeape being angry at her presence. Chikorita ignores them, so Primeape throws an object to her. Chikorita strikes with Vine Whip, defeating Primeape. The other Pokémon are not glad, so stare at Chikorita, angrily, but change their mood and become happy. Next day, the heroes see the tape script, where they see Chikorita running away. Joy sees this is the faze where Chikorita wants his attention by running away, while Pikachu followed her to reason with her. Ash sees he has to search for them, but Joy warns them there are tough Pokémon that can attack them. The heroes search, but see they need a plan. Brock believes Bulbasaur might get Chikorita's scent, so they will find her and Pikachu. Ash sends Bulbasaur, who leads the heroes in a direction. Jessie and James overheard that and plan to get to the boss Pikachu and Chikorita. James contacts Meowth, who scouts the land from the balloon, spotting Pikachu.
Pikachu came to the warehouse and reasons with Chikorita, who refuses to listen. Suddenly, Jessie and James appear and throw their net, but Primeape and the other Fighting-type Pokémon appear. Jessie and James intimidate them, but get intimidated by the Pokémon, instead. Meowth tells them to fight back, but gets asked to switch places. Meowth presses a button, activating a robot. The heroes heard the trouble and hope Team Rocket did not found Chikorita and Pikachu. As Jessie and James go to the balloon, they are terrified the robot is made of tires. The Fighting-type Pokémon strike, but get hit by the robot. Team Rocket are pleased about that invention. Chikorita goes to attack, but leaps before the robot attacks. Pikachu uses Thunderbolt, but it does not work, since the robot is made of tires. Meowth laughs at Pikachu's attempt, but Jessie and James got electrocuted. The heroes come and see as Pikachu and Chikorita get captured. The heroes see Pikachu cannot electrocute the balloon, so focus on the antenna on the robot. Ash sends Heracross, who licks Bulbasaur's tree sap and gets hit.
Ash orders Heracross to toss him to the robot. Misty warns him it is dangerous, but Ash knows he has to help his Pokémon. Heracross launches him, but Meowth presses the button, so Ash misses the robot. Ash stands up and sees the water tower nad climbs it. He goes to land on the robot, though the robot dodges (since Meowth caused it to move out of the twerp's reach). Fortunately, Chikorita uses Vine Whip to entangle him, to save him. Chikorita pulls him to the top of the robot, so Ash pulls the antenna out, making the robot frenzied. Chikorita and Pikachu are freed, so the robot pulls the balloon. Jessie and James ask of Meowth to pull them up, but Meowth tells he will use the claws to escape the robot, since they weigh down. Meowth cuts the rope, so they fall into the robot's helm. The robot explodes, so Team Rocket blasts off.
Later, Ash admits to Joy she understands Pokémon. Joy thanks him and wishes she could explore Chikorita's psych. Brock tells she can explore his psych, causing Misty to pull him away, calling him a psycho. Ash tells Pikachu to come and Chikorita to take her place at his other shoulder. With that done, the heroes go to Azaela Town.
- Ash battles a School Kid from Gen II in the beginning of this episode.
- This is another episode where a Nurse Joy wears a different outfit.
- The "Who's that Pokémon?" in this episode is Hoppip.