Whilst Ash and his friends are relaxing in a forest, three Mightyena and a Poochyena ambush them. While they are trying to protect themselves from the Pokémon, they are rescued by the Ranger of the Forest, Katrina. She wards off the wild Pokémon and takes the group to her house. Meanwhile, Team Rocket overhears that the forest is full of rare Pokémon. Back at Katrina's house, Max creates a bond with her Poochyena and tries to make it evolve, with minimal success. Is Poochyena going to evolve and is Max going to understand the importance of evolution?
May and Max spot a wild Zigzagoon which sees them and runs away. The reason are a pack of Stantlers. Ash finds it strange, with so many Pokémon around. Max tries to come closer to Shroomish and the Sudowoodo, but scares them off. May tells him that he should know how they look like because he studied, to which Max recites what he knows. Still, he is fascinated that he sees them up close.
Nearby, some Pokémon howl. Those are three Mightyenas who are angry. Ash thinks to retreat, but Brock advises to fight them. Pikachu, Forretress and Torchic come to fight them. A Mightyena attempts to strike, to which Pikachu uses Thunderbolt, however, the Mightyena evades. Forretress attacks with Tackle, but a Poochyena leaps and attacks Torchic and Ash. A woman appears, stopping the battle. The woman tells them that the area they are in is a Pokémon Preserve, but May says they are on their way to Rustboro City.
The woman addresses herself as Katrina, the ranger. The gang introduces herself, with Brock flirting with her. However, the Poochyena and Mightyenas attack Brock. Meanwhile, Team Rocket wanders the woods, searching for food. However, they spot a lot of Pokémon. Wobbuffet shows the sign, marking the area as a Preserve.
At a shack, Katrina shows the gang that she takes care of injured Pokémon. Brock tells Katrina that he's a doctor, to which the Poochyena strikes him. Max wonders why the Poochyena hasn't evolved, to which Katrina thinks the Poochyena didn't battle enough. Max tries to convince that the Poochyena has to evolve. May thinks what her Torchic would look like and wishes it to evolve. She checks her Pokedex - Torchic would eventually become a Combusken. Ash explains to them that the Pokémon needs experience and training to evolve.
Max and Max wonder why Ash's Pikachu hasn't evolved yet into a Raichu. Brock explaines the Evolution - some Pokémon need experience, while others (like Pikachu) need stones, like Electricity stone for Pikachu to become Raichu. Then Brock mentions Eevee, a Pokémon which can evolve into three different Pokémon - Jolteon, Vaporeon, Flareon (with usage of stones), Espeon and Umbreon (with more experience). Max wants to see the evolution of Poochyena and Brock wants to stay with Katrina, despite Ash wanting a Gym Battle.
Max trains Poochyena to attack with Bite, not only Tackle. Torchic attacks with Ember, defeating the Poochyena, even attacking Max. Max comes to Ash, wanting to borrow some of his Pokémon for Poochyena to battle. May says that Max wants them to lose on purpose for Poochyena to evolve. Ash tells him that some Pokémon don't want to evolve and want to be just the way they are, but Max is determined to battle more. Katrina arrives, showing a part of a net - poachers are in the Preserve.
Team Rocket has captured some of the Pokémon, but Meowth spots Max and the Poochyena. Max does not want Poochyena to battle Flying or Poison Pokémon, to even the odds. Team Rocket realize that Max wants the Poochyena to evolve. Max spots a strange machine, and as he was to walk away, Jessie and James (disguised) place Meowth in the machine. The result is that evolved into a Persian (although Meowth is disguised as well). To persuade Max more, they activate the machine and Persian is transformed into a Sunflora. Max finds this impossible. Meowth disguises himself as Aipom, Murkrow and Azurril, but with the rush, he transforms himself into a Persian/Sunflora/Aipom/Pikachu Pokémon. Despite Max's refusal, Team Rocket place Poochyena into the machine, making the machine exploded and the Team Rocket getting on the balloon.
The gang arrives, with Team Rocket unmasking themselves. James tricks Ash and Pikachu, capturing the Pikachu with the mechanical arm. The gang tracks the, with Ash bringing his Taillow. Taillow pecks Team Rocket, bringing the balloon closer to ground. Max atttempts to persuade Poochyena to use Bite attack, which (after several attempts) bites the net, setting itself and other Pokémon free. Pikachu lets himself free, using Thunderbolt to blast Team Rocket off. Max congratulates Poochyena, but it begins to glow, making itself evolving to Mightyena.
- "Now's your chance, Ash. Use that real-life experience you were talking about and make some friends!" - May
- Jessie mentions Albert Einstein, though she mistakes him to be inventor of lightbulbs. Max then corrects that Edison is the inventor.
- The Pokémon featured in the Who's That Pokémon segment is Hitmontop.
- This is the first time in Hoenn Ash does not use a Pokédex - in this case, Max examines the Poochyena with the Pokedex.
- This is also the first time in Hoenn that a Pokémon is shown on Pokédex, but it isn't examined on spot. In this case, it is a Combusken.
- This is the first time in Hoenn that Brock gets scolded for flirting.