During their journey to Hearthome City, Ash and his friends stop by a town and where they see a large crowd. Officer Jenny arrives and tells them if they are there to observe, they need to get in line. As usual, Brock falls in love with Jenny, swearing by her beauty that he will do what she wants, but Croagunk puts him down and drags him off. Jenny is bemused that they don't know the reason for the crowd - someone named Aaron is having a public practice session. Neither Ash nor Brock recognize the name, but after a pause, Dawn gasps and fishes out this month's PokéSheet, explaining that he is from the Elite Four.
The group decides to watch the practice, where Aaron is training with his Bug-type Pokémon Drapion, Skorupi and Vespiquen. Drapion uses Pin Missile, nailing the bull's eye of a far away target five times in quick succession. After congratulating Drapion, he orders Vespiquen to use Slash, which she does, easily carving up ceramic plates fired at her. In the crowd, Ash and Dawn gush about meeting another member of the Elite Four, remembering their meeting with Lucian. Jenny moans in excitement and recalls the Elite Four: Lucian and his Psychic types, Bertha and her Ground types, Flint and his Fire types and Aaron with his Bugs. She says that of the four, Aaron mixes strength with popularity the best.
Back at practice, Drapion uses a series of quick Hyper Beams, destroying the targets. Jenny gushes in excitement over how well Aaron speaks the language of Bug Pokémon and has perfect and amazing combinations. Brock chuckles and tells Jenny to control herself, but Jenny explodes in excitement as she reveals that Aaron has risen up and challenged Cynthia, and their battle to end all battles will take place soon. Dawn and Ash realize that Aaron was the challenger Cynthia had told them about back in Celestic Town. Jenny proclaims that Aaron, her hero, will undoubtedly be the winner. With a Gust, Vespiquen smashes all the remaining targets and ends the training session, thanking everyone for watching and asking for their support in the battle with Cynthia.
Inevitably, all the girls run up to Aaron asking for autographs, and Jenny jumps up demanding one too, but then blushes and remembers her duty, to ensure everyone is conducting themselves properly. Dawn jumps up and runs off for the line too. Ash happily asserts that one day he'll clean up at the Pokémon League and challenge Cynthia and Aaron.
Team Rocket is watching, and Jessie dreamily asks if they saw how impressive Drapion and Vespiquen were and suggests they steal them. However, James shrugs that he would end up with one of the Elite Four in his face, and Meowth reminds her that Aaron won't exactly hand over his Pokémon. They and Wobbuffet give up instantly and shuffle away, but she rushes after them and drags them back by their cheeks. She reminds them of how much money they will get if they sell them. James and Meowth fall in with Jessie's scheme and they prepare to morph into merchants for rare Elite Four Pokémon.
Aaron signs an autograph for a young girl, who barely containing her emotions, runs off telling him she'll remember the moment for the rest of her life. Aaron smiles at Dawn, noting that she's the last one and Dawn introduces herself and hands over her PokéSheet. She then boldly says that Cynthia told her that the Elite Four are powerful battlers and she would not go easy on him. Aaron is surprised and asks if they know Cynthia personally, which Dawn and the others confirm. Ash says they'll be rooting for both of them. Aaron notes that Cynthia is very powerful but he has been training even harder, which Drapion, Vespiquen and Skorupi make assertions in support of. Ash tells Aaron his dreams of perhaps one day even becoming an Elite Four member, which Aaron tells him to go for. He then invites them to his training center, which he would consider an honor from friends of Cynthia. Brock excitedly tells the others what a privilege this would be, and they reply that they would love to come.
At Aaron's center by the lake, Ash, Dawn and Brock look out at the view with Aaron and Skorupi. Aaron smiles and says he built the center after becoming a member of the Elite Four. Many wild Pokémon live nearby: Combee, Mothim, Ledyba, Surskit and Venonat frolic around outside. Aaron notes that the Bugs are enjoying the weather and releases Drapion and Vespiquen from their Poké Balls to relax after the mornings training session. He then goes and trains himself, explaining that his Pokémon would have a field day making fun of him if he didn't train as hard as them. Ash jumps on the bike, determined to train as well. Aaron warns him not to overdo himself, and Dawn exclaims at Ash's energy, whilst Brock says it's probably motivation from his rematch with Fantina. Looking around, Dawn spots a picture of a young Aaron together with a Wurmple.
Aaron's Vespiquen snoozes by a tree whilst Team Rocket sneaks up, having smeared honey on the tree. Meowth and James hurl a net forward, only to have caught a Munchlax. James is angry, but gets even angrier when Jessie reveals that she used his pancake syrup for the trap. James screams of disappointment arouse some Beedrill, who attack Team Rocket.
Aaron finishes training and takes his towel from Skorupi, whilst Ash has collapsed in exhaustion and Aaron suggests a break. Dawn asks about the Wurmple in the photo, and Aaron told them that Wurmple was his first capture, in the forest nearby. He had grown up in town and would sneak out to the forest as much as he could. As a small kid, he really liked to climb trees. One day he challenged himself to climb the lengthiest tree in the forest. However, once he got to the top, he realized how tall it was and how he could never climb down, but luckily there was a Wurmple on the tree who was able to help him, getting him safely down. Aaron grabbed Wurmple and hugged it in thanks. Aaron reveals that he and Wurmple were best friends and shows them photo albums of the two growing up. Ash reminisces about his first capture: the Bug-type Caterpie, which evolved all the way into Butterfree before he released it. He wonders about where it is and how it's doing.
Dawn asks where Wurmple currently is, but before he again answer, a giant suction hose activates, swallowing up Pikachu, Piplup, Skorupi, Drapion and Vespiquen. Aaron demands to know what is going on, and Team Rocket recites their motto. Brock explains Team Rocket's evil intentions. James and Jessie just gloat about successfully swiping Elite Four and twerp Pokémon. Aaron leaps into the air and nearly catches the balloon, but Seviper's Haze blinds him and he crashes to the ground. Team Rocket's balloon disappears over the tree tops as the friends rush to Aaron's aid. Ash decides that they have to follow after.
Jessie and James continue to gloat over their victory, but suddenly their balloon starts to rock as Pikachu, Piplup, Vespiquen and Drapion unleash their attacks on the inside of the huge tank holding them. The tank begins to smoke and spark and the balloon goes down whilst a nearby Ledian watches. Aaron is almost beside himself with anger at the theft of his Pokémon, but snaps back to reality at Dawn's words. He reveals that as a small kid, he was a real crybaby, and he was horrible at battling. After a loss to a Trainer, he blamed it on Wurmple, saying that Wurmple was weak, and ran off before Wurmple could reply. He later felt so awful that he ran back later in the day but it was too late and his best friend had gone.
It was this, Aaron reveals, that drove him to work with every Bug type he could until he could master their language, but he never wants to go through the pain of losing another friend, which is why he needs to recover Vespiquen, Drapion and Skorupi. A Ledian flies up and tells Aaron that it saw the balloon crash nearby.
At the crash site, Meowth is half cursing and half admiring the ability of the five Pokémon to ruin their escape. Jessie tells him to stop being so impressed and fix the balloon, hose and tank. At that moment, Pikachu kicks out the side and leads the other four to safety. James immediately calls out Carnivine, who as usual latches onto him in a back-breaking hug. Pikachu seizes the distraction to lead an escape, but Seviper cuts them off. Drapion leaps to the front and fights off Seviper, whilst Vespiquen jumps to help, but Carnivine hits her from behind with Bullet Seed, injuring her. Drapion is distracted and Seviper injures him with a powerful Poison Tail. As Team Rocket's Pokémon loom over Piplup, Skorupi and Pikachu, Aaron, Ash and the others arrive. Aaron pauses and recognizes a nearby tree as the one where he met Wurmple for the first time.
Meowth and Wobbuffet attack with the suction tank again, seizing Pikachu, Piplup and Skorupi, but Aaron dives on his injured Vespiquen and Drapion, keeping them safely on the ground. Pikachu and Piplup manage to each grab a branch and hold Skorupi in place, causing Jessie to curse and James orders them Meowth to amp up the suction. It rips branches from the huge tree, much to Aaron's anguish, and is too much for Pikachu and Piplup, whose grips break and they fly into the suction.
Suddenly a SolarBeam blasts out from nearby and obliterates the mecha, ending the suction and causing Pikachu, Skorupi and Piplup to fall to the ground. Their savior, a wild Beautifly, hovers down, evoking an emotional response from Aaron. He asks if Beautifly is in fact his Wurmple, which is nods in assent, much to Aaron's and the other's delight. Beautifly explains to Aaron that it wanted to get stronger, so it went off and trained before evolving into the Beautifly stage.
Jessie and James are still wanting their prize, so they order Seviper and Carnivine to attack, with Piplup and Pikachu teaming up against them. Seviper's Haze blinds both Pokémon, but Beautifly, under Aaron's command, uses Whirlwind to sweep away the clouds. Then Drapion's Hyper Beam takes down Seviper, and Vespiquen Slashes Carnivine into James. A combination of Beautifly's SolarBeam, Piplup's BubbleBeam and Pikachu's Thunderbolt sends Team Rocket blasting off.
Aaron thanks Beautifly for its help and asks if it would like to be a team once more. Beautifly happily accepts and it joins Skorupi, Drapion and Vespiquen on Aaron's team. Dawn says that she's so happy that Beautifly came home, and Brock says that Beautifly makes Aaron's team even more amazing. They then thank Aaron for a wonderful day in which they've learned so much, and he in return wishes Ash luck for his rematch with Fantina. Bidding Aaron and his Pokémon farewell, the group leave Aaron's center by the lake.
- Details of this episode were made known in K-Zone, a children's magazine, before any official Japanese episode listing. However, the magazine stated that Aaron would appear before Celestic Town, suggesting that it was moved to fit in the one-hour specials at Celestic.
- Aaron's signature was shown in this episode. It was his Japanese name in romaji, Ryou. This was not changed in the dubbed version.
- This marks the second time that Ash's Butterfree is seen in a flashback in the Diamond & Pearl series. The first was in The Thief That Keeps on Thieving! as a Caterpie.
- The dub title is a reference to the 1972 Paul Simon song "Mother and Child Reunion".
- Professor Oak's lecture: Charmander
- This episode marks the first time Brock's Croagunk is seen coming out of its Poké Ball before hitting him with Poison Jab.
- For a quick moment, while Ash and his friends are watching Aaron and his Pokémon perform, Dawn's purse overlaps Brock's pants.
- While Team Rocket discusses the advantages of stealing Aaron's Pokémon, Wobbuffet manifests itself right after a noise of it coming out of its Poké Ball, even though it was already out, as shown in the scene before.
- After Team Rocket's balloon crashes, Wobbuffet comes out of its Poké Ball while they are all on the ground. Shortly after that, Meowth is seen alone on the balloon, and Wobbuffet comes out once again of its Poké Ball. This is clearly a mistake, since the Poké Ball should stay with Jessie, and not Meowth.