After a practice battle between Ash's Chimchar and Dawn's Piplup, Chimchar begins to cry because Ash was nice to it even though it lost, and Paul wasn't. Things get worse when a trio of Zangoose attack and Chimchar has to face its fear and eventually defeats them and overcomes its fear of Zangoose. Chimchar also receives some unexpected advice from Meowth about the future.
Gardenia reappears in a town, organizing a special exhibition battle for the town's children. She teams herself with James of Team Rocket in a match against Ash and Dawn. She proposes that James should leave his Cacnea with her to train when he is unable to use it to its full potential. He eventually decides to accept the offer.
Buizel is more interested in Ash's gym training, and Aipom is more interested in Dawn's contest training. Thus, Zoey suggests that Ash and Dawn do a trade.
After Ash's Buizel destroys the Hallowed Tower, a Spiritomb is unleashed and attacks Ash, Dawn, Brock and a nearby village. Then Jessie tells it that Ash is a descendant of the Aura Guardian that coincidentally has a Pikachu, that sealed it away. So Ash sets out to stop the Spiritomb and with Pikachu's help, they seal it away in the Hallowed Tower.
Ash's group encounters a Pokémon Breeder working on the construction of a stone bridge. The woman is arguing with the bridge's designer because of their Pokémon assistant Bibarel's refusal to work. After the stone cutter returns, Bibarel begins to construct the bridge, with help from the gang.
Ash battles Alan, a trainer that wants his Nosepass to evolve into a Probopass, but it can only evolve if it levels up in Mt. Coronet. When it does, Team Rocket brainwashes it and now Ash & Co. have to get it back.
Ash encounter a young Officer Jenny named Marble and her Luxray. Luxray is unable to use its electric moves, so Ash & Co. set out to help it.
In Solaceon Town, Ash's group meets up with Dawn's old friend and rival Kenny and his new Pokémon, Breloom. Kenny tells them he is going to the Solaceon Ruins, a place of worship for the legendary Dialga and Palkia, so they tag along, only to get more than they bargained for when the Unown that live in the ruins become furious along with the appearance of the sinister Team Galactic. Among the chaos, Aipom evolves into Ambipom
Dawn competes against Kenny in the Solaceon Town Contest, looking for redemption after her crushing loss in Hearthome City. Jessie of course enters. Dawn loses once again and Kenny and Jessie face-off in the finals. Jessie defeats Kenny and wins her first ribbon. Zoey tells Dawn that the overuse of Swift caused Ambipom to be no longer seen and the point of an Appeal is to show off the Pokémon.
On their way to Veilstone City, Ash and his friends stop off at the Mountain Hut Maid Café for a nice drink of Miltank's Milk. However, when they arrive, they learn of the troubles the Café is having, being under-staffed. Ash and his friends offer their services and soon become Maids in the Café. Brock helps Autumn, the youngest of three sisters bond with her Miltank, Ilta. All the while Dawn is trying deal with her feelings of losing a contest for a second time.
Ash and his friends stop at a Hot Spring managed by Dawn's childhood friend, Leona. Both girls are happy to meet again, but when Dawn and her friends want to go to the hot springs, they find out that there isn't any water. Because no water is coming from the spring, the group want to investigate, along with Leona and her Swinub.
Ash and company visit a town where it is plagued with a group of Gligar led by a Gliscor. Ash and friends help Officer Jenny try to remove the flying Pokémon, while Ash's rival Paul sets his eyes on capturing Gliscor. In the end, Paul captures the Gliscor on his team, and Ash captures one of the Gligar that keeps showing up.
When our heroes' Pokémon are having a fun time in a sandpit, a Hippowdon appears from within. However, the over-curious Pachirisu can't help peeping into the Hippowdon's mouth and accidentally falls into it. The situation gets worse when Hippowdon becomes the target of the Team Rocket duo Butch and Cassidy.
In the forest just outside Veilstone City, the group witness a young female martial-artist and a Lucario in a fierce battle. The girl is revealed to be Maylene, the city's Gym Leader, at which point Ash immediately asks for a Gym Battle. However, she recently lost to Ash's rival Paul, and is depressed over her defeat. Further insight into the matter is revealed by Reggie, Paul's older brother. Reggie also helps Ash's Staravia learn Brave Bird.
Dawn challenges the gym leader of Veilstone City, Maylene, in hopes of helping Maylene get over her defeat. Maylene defeats Dawn and she and her Lucario regain their confidence.
Maylene finally accepts Ash's challenge. Ash uses Staravia, Chimchar, and Buizel against Machoke, Meditite, and Lucario. The battle between Buizel and Lucario ends up in a tie but Maylene still gives Ash the Cobble Badge.
With Ash acquiring the Cobble Badge, our heroes decide to spend the night in Veilstone City before heading out. Reggie takes the group to a park with several meteoric stones lie. However, Team Galactic appears and try to steal them for their world domination plans.
While training Gligar, Ash hears singing. When they look to see who is singing, they meet a magician named Francesca and her three Chingling. Francesca is trying to get her spoiled Chingling to have a better attitude.
On their travels, Ash and his friends meet up with another Pokémon Ranger—Kellyn—and a Riolu. It turns out that Hunter J is after Riolu, due to its ability to use Aura Sphere before evolving. Ash and Riolu start to bond with their shared Aura, but J is insistent on getting it. This episode relates to the secret mission in Pokémon Ranger: Shadows of Almia, from which the player can transfer a Riolu that knows Aura Sphere to their copy of Diamond, Pearl, or Platinum.
Hunter J has managed to kidnap Riolu. But despite that, Riolu, reveals his whereabouts to Ash, using its Aura. With Rangers Kellyn and Solana joining them, Ash and his friends go to hunt down Hunter J and get Riolu back. However, J is far more formidable than anyone could have anticipated. Will Ash and friends be able to return Riolu back to its kingdom?
Ash and Co. arrive at a lakeside Pokémon Center. Jessie's Dustox sees a shiny Dustox, and follows it to the lake. Jessie releases her Dustox, allowing it to mate. This is related to the Season 1 episode 21, "Bye Bye Butterfree" where Ash releases his Butterfree so it can mate with a pink Butterfree.
Ash and his friends meet Sho, a boy who has a Pichu and a Raichu. He mistakes Ash's Pikachu for a wild Pokémon. Just like at the Vermillion City Gym, Ash and Pikachu have the option again to evolve Pikachu to Raichu, after a loss to a stronger opponent. Paul witnesses this defeat and scolds Ash for losing to such an opponent, but manages to redeem himself of that defeat in a rematch.
Ash, Brock and Dawn meet the Champion of the Hoenn Region, Wallace. He says he will be holding a Pokémon Contest and the winner receives a ribbon that can be used anywhere. The group spends the day with him, resulting in advice from Wallace for Dawn to play with her Pokémon more and for Ash to enter Buizel in the contest. At the end of the episode, Ash receives a phone call from his friend, May.
Ash and Brock's old friend May, still training to become a Top Coordinator, visits Sinnoh for the Wallace Cup. Upon arrival at the Seven Stars Restaurant, they find out that only those who win a tag-battle against the restaurant's owners can eat there. Ash partners with Brock and win the double combat with a single move. Before Dawn and May's combat, Team Rockets steals all food from the restaurant. May and Dawn partner up and defeat both the Team Rocket and the restaurant's owners, the later by using Blaziken and Piplup together to create a fantastic fire/water combination. There is a cameo from Drew, Harley, and Max.
Ash and his friends have arrived at the Lake Resort where the Wallace Cup will take place. Zoey also arrives, and competes, too. Right when the contest began, Dawn becomes nervous and has trouble keeping her composure. Meanwhile, May decides to enter with Wartortle, and Ash enters with Buizel. There are cameos of Drew, Harley, Max, Norman, Caroline, and Solidad.
At night, Ash takes a walk near the Lake Valor with Pikachu when suddenly, something in the center of the lake begins to glow, and it turns out that Azelf appears. When Ash tries to approach it, the shadow disappears again. The next day, the second round of the Wallace Cup begins. May's Venusaur is then revealed, and there is a cameo appearance of May's Skitty battling in the second round. Dawn, May and Zoey make it to the semi finals but Ash loses to a tough coordinator called Kyle. After it is Dawn's turn to battle Kyle in the semi-final, she uses Piplup against his Crawdaunt. There are cameos of Norman, Caroline, Max, Kenny and Paul.
Dawn beats Kyle and May beats Zoey in the semi finals and both have to battle in the finals. In the finals, Dawn faces-off against May in the Wallace Cup. Dawn uses Piplup and May uses her Glaceon. Dawn manages to narrowly defeat May's Glaceon by a fraction. After the contest ends, Dawn earns her second Ribbon! Now that the contest is over, May departs from Ash, Dawn, and Brock once again and goes back to Johto.
When on their way to Pastoria City, Ash and friends meet a trainer named Tyler that wants to catch a Yanma. But Team Rocket ends up catching it after he weakened it. After Jessie captures the Yanma and sends it to Giovanni, who rejects it, she decides to train it herself and it quickly evolves into Yanmega.
Ash and co. are running after Gligar who has been blown away by a gust, and promptly run into Paul. After a huge argument about their different ways of treating Pokémon, Ash challenges Paul to a battle. But when Chimchar is battling Paul's Ursaring, it activates an overpowering blaze. Chimchar also gets confused and starts randomly attacking anyone in its path.
After Ash & Co. arrive in Pastoria City, Crasher Wake refuses Ash's request for a battle because he has to take care of something. They tag along and find out there is a Croagunk Festival in the Pastoria Great Marsh.
At the Pastoria Gym Ash challenges Crasher Wake to a 3-on-3 Gym Battle using Pikachu, Turtwig and Buizel, while Wake uses Gyarados, Quagsire, and Floatzel. However, Pikachu accidentally shocks Buizel and this causes them to argue which makes a difficulty in helping Ash defeat Wake. Suddenly, thanks to that Buizel had rescued Pikachu from the attack; their argument concludes. Ash manages to defeat Wake and he earns the Fen Badge.
A Swinub shows up at Mr. Backlot's mansion and starts to eat all the Poffins. Dawn tries to stop it by making her own Poffins for Swinub. Dawn ends up capturing Swinub at the end of the episode.
Ash continues his training with Gligar, but finds out it has become fearful of battles since the battle against Paul's Gliscor. The group meets Gary again, and Ash asks Gary to help him solve the problem with Gligar, and Gary gives Ash a Razor Fang, which makes Gligar evolve into Gliscor.
Ash and friends return to Hearthome City to challenge the Gym Leader who was gone during their last visit. However, they hear that the Gym Leader is still gone, making Ash unable to have his fifth Gym Battle. The group meets Paris, a Pokémon Stylist, and her Lopunny. She suggests that Dawn should enter the Hearthome Collection, a famous fashion show.
While traveling through a deep valley, Ash and friends encounter a swarm of Psyduck in the middle of a road. Upon trying to pass them, the Psyduck suddenly start attacking them, and to make things worse, when ash and team try to battle them there are too many to battle so ash sneaks behind them with the help of gliscor only to know that psyduck is trying to protect their families who are waiting to hatch their eggs and doesn't want people to interrupt. when team rocket tries to steal the pokemon with the help of psyduck they manage to blow them away and saves the day. Ash and team goes to check psyduck's home lake they find mug has taken the lake, ash and team fights the group of mug and takes back the lake for psyduck
When Ash & Co. are invited to attend a Pokémon Academy, they decide to enter it. For their first task, they choose a PokéBall that contains a Pokémon inside. The trainer then has to train the Pokémon and be able to use it in battle. The gang then meets Angie, and meets Conway again.
While at a Pokémon Academy, Ash, Dawn, Brock, Angie, and Conway find that their Pokémon are becoming hypnotized when they go near a lake. So they decide to go and investigate what's going on.
While Ash and friends are training at the Summer Academy, they are taught how to deal with Ghost-Type Pokémon, should they ever run into them. They are then paired up to find a hidden treasure. While searching, Conway has a run-in with a Dusknoir.
After the Trainers are finished with the training, they must use a Pokémon to bring them across a rigorous track to the finish line. Finally after a tough competition Ash and Pikachu came first, and Angie and Shinx came second which led to the victory of the red team. Everyone is given a certificate. They said good bye, and the team continued their journey.
On their way to Celestic Town, Ash and his friends have to take Piplup to the Pokémon Center after it collapsed from over-excessive training. Meanwhile, Team Rocket, who were following the group on a slope, decide to have lunch in a luxury restaurant. But then Jessie notices that Meowth's golden charm is buried under rolls of flab. The trio now realizes that, due to them having led a rich and luxurious life ever since they had earned the money at the summer school, they have become lazy and grown a lot in flesh. Wanting to return to their former "sharp and cool" shapes, they start a harsh training session.
Zoey is facing a critical situation against a very tough coordinator. With her Glameow confused, the battle ends quickly. Ash and co. cheer for Zoey who was defeated by the mysterious trainer. This mysterious trainer is none other than Fantina, who like Hoenn's Juan is a coordinator and the Hearthome Gym Leader. Ash requests that he battle her and she accepts. How will this battle turn out? And can it prepare Ash for his actual Gym Battle?
Brock is away on an errand. When they can't handle it, they send Gliscor to bring Brock back. Brock finds he can't carry Gliscor back, as it can't glide in the wind going the opposite direction, and leaves it, promising to return for it. At the end of the episode, the gang comically realizes that they left Gliscor behind, and scene shows a frustrated Gliscor with a long way to go.
Dawn has entered the latest contest held in Celestic Town. Dawn meets her mother's old rival Yuri, that wants to win this contest. When she and her mom's rival "Lila" (Yuri in Japanese version) come face to face in the Finals of the contest Dawn has to give it all she has to win. Dawn wins the Celestic Town ribbon and her third contest ribbon.
Commander Mars and Cyrus (not known yet by Ash and co. that he is a part of Team Galactic) debuted in the anime along with Commander Saturn and the other Galactic grunts . In this episode, they steal the Lustrous Orb and the Adamant Orb from the Celestic Town museum for the power to awake Dialga and Palkia in their future plans.
In this episode Commander Jupiter is introduced. Ash and the gang are helped by Cynthia to stop Team Galactic from stealing the Lustrous Orb and the Adamant Orb, but they fail because they had no idea how large Team Galactic was.
Arriving back in Solaceon Town, the gang meet up with Angie at her Parent's Daycare. She tells them her parents are gone for a while, so she leaves the daycare to her for a while. Ash and the gang tell her about the strange monster terrorizing Solaceon Town. She later reveals that the monster is a Lickilicky that she evolved from a Lickitung which she taught it Rollout. So the gang goes out and helps her find the Lickilicky and bring it back. At the end of the episode, it is revealed the Angie may have a crush on Ash.
As Ash and the gang are heading back to Hearthome City, they encounter Aaron, a member of the Elite Four. They see that he's training his bug Pokémon, but also himself. He explains to the gang that he's trying to look for a Wurmple he released as a child as he felt it could become stronger on its own, but he wants him back. The gang offers to help Aaron look for his released Wurmple. They find Aaron's Wurmple, but since then it has evolved into Beautifly. The two become a team again. In the end, Aaron happily says thank you and a farewell, and Ash and his friends head on to Hearthome City.
Ash has a battle with Paul. Choosing a one-on-one battle, Paul chooses Honchkrow, and Ash chooses Turtwig. Honchkrow manages to drive Turtwig into a corner, but at the last moment, Turtwig evolves into Grotle. However, Grotle loses all its agility and loses to Honchkrow anyway. Paul then reveals to Ash that he has already obtained the Hearthome City gym badge. Afterwards, Brock confronts Paul that he met his older brother Reggie over a missing Frontier Brain symbol, which in turn, partially reveals Paul's captious nature of becoming strong. Grotle gets up late that night and unsuccessfully tries to regain its agility. Paul's Torterra shows up and comforts Grotle by showing it that speed isn't everything about battles. Torterra tells Grotle that it can also rely on defense. Torterra shows an example with Ash's Gliscor using a Steel Wing straight to the head. Torterra emerges unscathed, and Grotle resumes to its normal behavior.
Upon arriving at the Hearthome Gym, Ash and his friends run into Barry, a trainer from Twinleaf Town. Barry turns out to be an admirer of Paul, whom he saw when watching the Double Battle Tournament. Ash challenges Barry to a Pokémon battle. Ash chooses Chimchar, Gliscor, and Pikachu, against Barry's Staraptor, Roserade, and Empoleon. Ash manages to narrowly defeat Barry, finishing off Empoleon with Pikachu's Volt Tackle.
The Gym battle between Ash and the Hearthome Gym Leader Fantina has begun. Ash chooses Buizel to battle Gengar, Chimchar to battle Mismagius, and Pikachu to battle Driftblim. Using his new counter-shield strategy Buizel defeats Gengar, Chimchar defeats Mismagius but Pikachu gets defeated by Driftblim when Fantina uses her own strategy against him, Buizel also gets defeated by Driftblim, but Chimchar finally defeats Driftblim, and Ash wins the Relic Badge. Barry, having seen Ash defeat a Gym Leader he lost to, declares that Ash is a rival if Ash can beat the leader of the Canalave Gym. Meanwhile, Jessie, as her alter ego, Jessilina, wins her second ribbon using her Yanmega in the Majolica Town Contest!
Ash and company, along with Barry, take a ride in a blimp to Canalave City. When they arrive, Team Rocket, disguised as photographers, trick them into taking a picture of all of their Pokémon, which actually turns out to be a net to kidnap them. The Pokémon fight back to attempt to escape, and everyone's Pokémon (including Team Rocket's) gets blown away into the sky in the process and they all get separated. A chase ensues when Team Rocket declares that whomever should find the Pokémon first, gets to keep them all. When Meowth is grouped with Pikachu, Pachirisu, and Mime Jr. after the explosion, he considers leaving Team Rocket for good. Can all of the Pokémon find their trainers?
The group heads to the Canalave Gym, but they are told that the Gym Leader isn't there right now. At a police station, the group is told by Officer Jenny that all the people in the town are having nightmares, and that the cause of the nightmares seems to be the Pokémon Darkrai. Also, Dawn's Swinub evolves into Piloswine in order to stop Team Rocket from stealing Cresselia.