On the way to the Battle Pyramid, Ash and friends are attacked by a wild Weavile and Aipom is seriously injured. They find out that this has happened to many Trainers lately. They decide to help a man named Kerrigan to find out why this exiled Weavile is attacking people, but they must also take care of Team Rocket who is gunning for Weavile!
The heroes are traveling through a forest. Aipom annoys Ash, but soon, they reach a valley. Pikachu and Aipom play around and the heroes rest for a while. Aipom goes to smell the flowers, but gets lost among the grass. A wind is blowing and Aipom turns, seeing a strange Pokémon with a scar under its left eye. The Pokémon uses Shadow Ball, attacking Aipom and the heroes rush to go to that place. Max identifies the Pokémon to be a Weavile. The Weavile uses Shadow Ball, but the heroes evade the attack.
The Weavile uses another Shadow Ball, but the heroes evade that one as well. Pikachu uses Thunderbolt, but the Weavile evades quickly the attack. Weavile uses Shadow Ball, hitting Pikachu. Aipom uses Swift, but misses. Aipom uses Double Team and go to attack. Aipom uses Swift, but the Weavile dodges and attacks the real Aipom with Shadow Ball, hurting it severely. When they look for Weavile, the heroes do not see it anymore. A man comes and tells he saw the battle and tells they need to go to heal Aipom. Team Rocket saw the battle and Jessie has the idea of getting that Weavile for herself. Jessie tells Meowth and Weavile are like day and night, angering him. Jessie and Meowth bicker and James already suspects something will go wrong.
At a lodge, the man, Kerrigan, tends to Aipom. Kerrigan says Aipom will recover after some sleep. Still, the Weavile attacks - it just parted with the rest of Sneasel and Weavile and now attacks people and Pokémon. The heroes offer help, but Kerrigan hesitates, as it will get rough. Still, Ash tells he cannot allow the Pokémon to be beaten like his Aipom, so Kerrigan accepts their help. The Weavile remembers it limped away, even if a Sneasel wanted to stay with the group and goes away. Pikachu smells Weavile's tracks, so the heroes and Kerrigan follow him. Meowth approaches Weavile (being disguised as a Weavile itself). James thinks this will not work, but Jessie convinces him otherwise. Meowth tells he came from a magic forest and the Weavile tells him he will be attacked by a Shadow Ball if he trespasses, making Meowth run away to Jessie and James.
The heroes come and Pikachu and Weavile bicker - Meowth translates that Pikachu asked it why is it doing this, so Weavile replied it does not have to answer to him. Meowth cannot translate the rest, so Jessie gets mad and now blows the cover - the heroes now know Team Rocket are behind the bush. Jessie tries to convince Weavile to join her, confusing everyone. However, a Sneasel comes and Meowth begins to translate. Sneasel tells it is escaping - the Weavile and Sneasel were living together in peace until a particular Weavile came to become the leader. That Weavile attacked the other Weavile, leaving a scar under the left eye - the same one who is near everyone. The Weavile escaped and promised to be better and stronger.
Weavile tells it does not need anyone, but the Sneasel came, as it did not wanted to be forced to live under the rule of the rouge Weavile. Suddenly, the other Weavile appears. Jessie goes to get it, but the abandoned Weavile blasts her, James and Meowth with a Shadow Ball. Ash tells the Weavile it will just let the Weavile leader take the Sneasel, convincing it needs to fight back. Pikachu uses Thunderbolt to attack the other Weavile, leaving the leader and the abandoned one stand. The Weavile attack - the leader uses Shadow Ball, but misses, so the abandoned one uses Shadow Ball as well. The ball hits water and the leader comes out, going to scratch the abandoned one. The abandoned Weavile blocks the attack and knocks it to water. Abandoned Weavile uses Shadow Ball, but the leader is missing. The leader uses Shadow Ball and goes to scratch as well, so the abandoned one remembers the last time it used the same strategy.
So, the abandoned one dodges and blocks the leader's Scratch attack and knocks it to the ground. The abandoned Weavile goes to attack, but stops - it became the leader. The Sneasel comes and forces both of them to shake hands, to make a truce. Korrigan believes things should be fine now and sees the abandoned Weavile (now the leader) thanking Ash for the words. The Sneasel and Weavile leave them, while the heroes and Korrigan go to Korrigan's house. Korrigan wishes Ash luck in the Battle Pyramid and the Aipom runs away from Ash. The heroes wave goodbye to Korrigan and go to get Aipom back.
- The instrumental version of 小さきもの A Small Thing from Jirachi: Wish Maker was used as background music.
- Ash's Aipom remains outside of her Poké Ball throughout this episode.
- In one scene, one of the Weavile's ear feathers is blue instead of the usual red.
- Ash's Aipom takes damage from Weavile's Shadow Ball even though Ghost-type moves do not affect Normal-type Pokémon. This is an example of anime physics.
- Ash's Aipom appears to be bigger than Pikachu in the scene it is walking with Ash, when normally Aipom is about the same size.