If Gary Oak is headed for the Sinnoh region, then Ash Ketchum won’t be far behind! Ready to take on the Sinnoh League, Ash brings along Pikachu and meets up with Brock in Sinnoh, where the pair of Trainers are soon joined by a third—Dawn, a novice Pokémon Coordinator determined to follow in the footsteps of her mother. Both Ash and Dawn struggle with their respective paths, but it’s easy for them to make new friends, gaining new Pokémon like Turtwig and Piplup.
In the far-off region of Sinnoh, a girl named Dawn has reached her 10th birthday and has set out from her hometown of Twinleaf to meet Professor Rowan in Sandgem Town to receive her Starter Pokémon. Her dream is to take part in Super Contests positioned throughout the land. On her way, however, she gets lost. When she manages to reach the Lab, the three Starters, Turtwig, Piplup, and Chimchar, are fighting and manage to escape the building. Now it's up to Dawn to get them all back so she can begin her journey.
After getting her starting Pokémon, Piplup, Dawn begins her quest to compete in Super Contests. After many failed capture attempts, she runs into Ash's Pikachu who is still separated from Ash and she tries to catch it. The capture fails because Pikachu is already someone elses Pokemon. Then Team Rocket come and attack Pikachu! Meanwhile, Brock returns with new clothes and him, Ash, and Aipom set out to find Pikachu. Can they find Pikachu? and can Dawn save Pikachu?!
Paul challenges Ash to a battle, however, since he has not found Pikachu yet so he has to decline. Finally, Ash finds Pikachu with Dawn. After thanking her, he returns to Sandgem Town along with Brock and Dawn where Paul challenges him again, and he accepts.
After Dawn fails to capture a Buneary, her and Ash begin to fight constantly. They soon run into a trainer named Nando who temporarily stops the fighting. Dawn decides to battle Nando in order to prove to Ash that she is better then he thinks. However, Nando's Budew easily beats Piplup. At the pok�mon center Nurse Joy tells them that he is trying to decide between contests and gym battles. Ash and Dawn decide to try and "help" him decide. Meanwhile, Team Rocket decides to attack Dawn thinking that because she is a new trainer, they can easily beat her.
On the way to Jubilife City, Team Rocket captures Pikachu and flies off. After Starly pops the balloon, a wild Turtwig sends Team Rocket blasting off before running into the woods with the injured Pikachu. Ash, Brock, and Dawn meet Clara who lives on the lake and she explains that Turtwig helps injured pok�mon and tires to keep peace in the forest. Ash, Brock, and Dawn go into the woods to find Pikachu and Turtwig, and Team Rocket is planning on stealing both.
While preparing a to eat one of Brock's meals, Aipom and Piplup get into a fight which Turtwig tries to break up. Paul shows up and seeing Ash's new Turtwig, he wants to battle it. During the battle Turtwig will not dodge attacks which worries Ash. Team Rocket then interrupts and Ash and Paul wind up going over the cliff side. At the bottom of the cliff is a forest where wild Stantler live and create illusions so that they will not be disturbed. Now Ash has to make it out of the forest without the interruptions of the Stantler, as well as some Beedrill and Ursaring.
Ash and Brock help Dawn train for an upcoming contest. However, her planned appeal always makes Piplup dizzy and it always fails. While they prepare to eat lunch, Team Rocket finds a pile of berries belonging to a Golduck, Wooper, Quagsire, and Poliwag, and steal them. When some of these berries wind up with some Ludicolo, Golduck begins to yell at the Ludicolo. Team Rocket attacks Golduck and sends it flying so that Ludicolo will join there side. Soon, Piplup winds up leading the Golduck to fight the Ludicolo and Team Rocket in what will be a Water Pok�mon showdown!
Team Rocket open a Gym in hopes of scamming people of their Pokemon. However, Jessie can not win a single match. Her luck changes when a Croagunk follows Meowth from the store, and soon she is winning every battle. Ash and friends run into a girl name Minnie and she is headed to the Gym. Ash decides to go with her. When Minnie loses, she lets them take her Scizor to train it. However, this is Team Rocket's plan, to steal the Pokemon. However, when Ash wins they steal Pikachu and run. Can Ash get Pikachu and all the other Pokemon back, and what surprise does Croagunk have in store?
While everyone is getting ready for breakfast, Dawn is in the middle of a hair fiasco, which eventually gets solved with Bubblebeam from Piplup. Before breakfast, Dawn once again fails at capturing a Buneary. During breakfast Dawn leaves to chase it down, but Buneary freezes everyone (minus Pikachu, Starly, and Croagunk), and bounces away with Pikachu. Team Rocket then decides to capture the pair of Pokemon.
Ash and friends finally arrive in Jubilife City, and Dawn is ready for the upcoming Pokemon Contest. However, she wants to go get a Poketch for the contest, but they are all gone! At a street corner, Team Rocket disguised as clowns are giving free ones out, and Dawn, Ash, and Brock take one. At a park, a boy comes up to them and reveals that they are fake. It turns out that the fake ones are a scheme to hypnotize the Pokemon of the trainers who took one and capture. However, Ash, Dawn, and Brock soon catch onto this and plan to stop Team Rocket.
The Jubilife contest is about to begin and Dawn is excited for her first contest. She comes across Zoey, a girl who will also be competing in the contest. While practicing with Ash, Aipom interferes in her battle and Dawn convinces Ash to join the contest. As the two get registered, Jessie will also be entering the contest with James' Carnivine, while James and Meowth sell fake seals. As the contest begins, Dawn is nervous while Ash and Jessie are confident. Can Dawn win her first contest?
The battle rounds of the Jubilife contest are about to begin and Ash, Dawn, Jessie, and Zoey all make it to the finals. Tension rises quickly between Ash and Zoey when Zoey finds out that Ash also enters Gym Battles. Their battle is up first, and although Ash puts up a good fight, Zoey wins in the end. As the next semi-finals begin, Dawn must beat Zoey. Will she be able to beat Zoey and Jessie and win her first ribbon?
On the way to Oreburgh City, Ash is training Starly so that it will learn Aerial Ace. During the training they meet a girl named Rosebay whos job is to protect the wild Pokemon in the valley. She has noticed that the population of bird Pokemon has decreased over the last copule of days. In turns out that this is all a plan by Team Rocket, who is capturing them inside of an underground base. When Starly winds up in this trap, he tries to rally the Pokemon into trying to break free.
During the middle of the night, a Nuzleaf falls from its home in a tree and it carried across the forest by a Vileplume. The next day Nurse Joy tries to help it, but Nuzleaf just attacks her. Ash and friends come by and try to help. However, Team Rocket soon attacks and they capture Nuzleaf, Bonsly, and Brock! Brock tricks them into letting him loose from the tree he is tied to in order for him to cook a meal for them. While Team Rocket is eating, Brock grabs the Pokemon and escapes. During the escape, Bonsly evolves into Sudowoodo. Now, Brock must get Nuzleaf back to its tree, meet up with Ash and Dawn, and fend off Team Rocket!
Ash and friends finally arrive in Oreburgh City. They head to the Gym and run into Paul. It turns out that Roark, the leader is working at the Oreburgh mines. After digging up a fossil, Roark returns to the Gym and begins his battle with Paul. The realization of Roark's power comes into view when he easily takes out Paul's Azumarill. As the battle continues, Paul now has to face three rock-types, with his only type advantage knocked out. Will Paul be able to pull off a win?
Ash's match against Roark must be put off until the morning so that Roark's Pokemon can heal. At the Pokemon Center, Ash is picking his line-up as Paul picks up his Pokemon. After finding out he gave away Azumarill, tensions between Ash and Paul heat up even more. Paul decides to watch Ash's battle, which he soon regrets when Aipom is quickly defeated by Cranidos. When he sees the power of Pikachu, he decides to stay. Ash manages to defeat Cranidos with Turtwig, but he still has Onix and Geodude to deal with. Can he win his first badge?
Ash begins training with Brock for his re-match against Roark. Dawn decides to train for her next contest. Meanwhile, Team Rocket finally steals the fossil machine from the museum, hoping to resurrect tons of fossil Pokemon for Giovanni. When the first fossil is regenerated, the Aerodactyl flies away and begins to terrorize Oreburgh City. Soon, a Kabutops and Armaldo break free from the museum and join Aerodactyl in the rampage. Now, it is up to Ash, Dawn, Brock, Roark, and Officer Jenny to stop them.
Ash returns to Oreburgh Gym, ready to challenge Roark again. As the battle starts, Ash quickly surprises everyone when Pikachu manages to take down Onix. As the second battle begins, Ash pits Aipom against Geodude. After a long struggle, Ash manages to beat Geodude, and loses Pikachu and Aipom before the real test begins, defeating Roark's newly-evolved Rampardos.
After staring at a Pachirisu for some time, Dawn decides to capture it. After she captures it, she is immediately attached to it, loving to spend time with it. However, Pachirisu's playful nature causes Dawn to freak out and doubt her abilities as a trainer. She decides to release Pachirisu, and runs away. Jessie sees this and decides to capture the Pokemon for herself. However, Dawn begins to have second thoughts and decides to re-capture Pachirisu.
On the way to Floaroma Town, Ash and the others hear some screaming nearby. At a house, a Pokemon hunter named J has just captured a girl named Melodies Gardevoir and she quickly flees the scene. Ash gives chase to her, and tries to battle her, only to have Pikachu frozen in stone and stolen just like Gardevoir. They decide to help Officer Jenny and try to help capture J, but eventually she also gets Meowth as well! Before she can take off, Ash, Jessie, and James sneak under her vehicle and follow her to her secret flying base. Now, the reluctant allies must work together to get back their Pokemon from Jes clutches.
Ash and the others return to Jubilife City, needing to go through the town to get to Floaroma Town. The end up at the headquarters of the B Button League, a group of people who want to get their pok�mon to be strong and beautiful without evolving them, as well as their leaders, Haley and Oralie. Meanwhile, the Magikarp salesman once again swindles Team Rocket. This time he gets them to buy a machine that will force Pokemon to evolve. Ash decides to battle Oralie, and she will be using her Magikarp. Despite being at an advantage with Pikachu, the Magikarp still beats both Pikachu and Piplup! After seeing Magikarp's power, Team Rocket decides to steal Magikarp and Feebas and force them to evolve, giving them a powerful Gyarados and a beautiful Milotic, not to mention they also steal Pikachu and plan to evolve it into Raichu. Now, Ash and the others must get their Pokemon back before Team Rocket makes them evolve, and ruins all their hard work.
On the way to Floaroma Town, Dawn finds out that a unofficial Pokemon contest is being held nearby, and Dawn wants to enter it for some practice. Ash's Aipom then steals his hat and runs off. Aipom accidentally ends up on a cliff, and is about to fall off when Team Rocket passes by. Jessie saves Aipom, and when Ash and the others arrive, she demands that she wants to use Aipom in the Pokemon contest as a reward for saving it. Ash reluctantly agrees, but soon regrets it when he thinks Aipom likes Jessie more then him. With the contest beginning, Dawn is entering her Pachirisu and Jessie will still enter with Aipom, but will Ash be okay with the result?
Team Rocket are planning their next pitfall trap, and like usual, they get themselves into trouble. While digging, their shovels suddenly get stuck in the ground. When they try to pull them out, a Steelix pops out of the ground, with the shovels stuck in its head! The Steelix grows angry and begins to chase them. Meanwhile, Ash and the others discover an injured Bidoof. After healing it of its injuries, they decide to help it back to its village. However, Soon Team Rocket and the rampaging Steelix come by, forcing them to run to the Bidoof�s village. Lucky for them, the Bidoof village is surrounded by a huge rock wall, but Steelix will be able to break through soon. Now Ash and the others must figure out how to stop Steelix before he destroys the Bidoof village.
On the way to Floaroma Town Ash and friends arrive at a cake shop where they meet Theresa and her aunt Abigail, who run the shop. They find out that a annual bake-off will be held soon and usually Abigail wins it making her special cake with her Pikachu, Sugar. However, Sugar recently left leaving Abigail sad and debating whether or not she will be entering the contest this year. Theresa convinces Ash to let Abigail borrow his Pikachu for the contest, and pretend that it is Sugar, and he agrees. However, Team Rocket once again threatens to ruin the plan.
Ash and friends finally arrive in Floaroma Town, the site of the next Pok�mon Contest. Dawn learns that a class about cooking Poffin will take place that day and wants to join so that she can use them to win the Floaroma Contest. When they arrive at the place they are greeted by Forsythia, the class teacher. As the class begins Ash's poffins turn out burnt while Dawn's taste bad. As they try to make better ones they learn about Forsythia's shy Roserade and how it does not like to be around people. However when Team Rocket attacks, Roserade might be their only hope.
Ash and Pikachu are helping Dawn to train Pachirisu to control its electricity. During the training one of Dawn's childhood friends named Kenny arrives at the contest hall. He immediately begins telling Ash and Brock funny stories of Dawn which gets her angry, not to mention he has a Prinplup, the evolved form of Piplup. Kenny reveals that like Dawn he also lost to Zoey and her Glameow. While they catch up and Kenny and Ash battle, James and Meowth are sent on a mission to find a new contest pok�mon for Jessie. Their target just happens to be Kenny's Prinplup.
As the Floaroma Town contest begins, Pachirisu�s stage fright puts Dawn in a state of panic. However, Dawn pulls out a Poffin which snaps Pachirisu out of it, and she puts on a great appeal. While she worries weather or not she will make it to the next round, Jessie and Kenny pull of great appeals, and soon all three of them make it to the next round. In the first round, Dawn must face Jessie. After struggling for a little bit, Dawn manages to pull off a win. As the contest winds down, the final battle is Dawn vs. Kenny. Will Dawn beat her childhood rival and win her first Contest Ribbon.
On the way to Eterna City, Ash and the others arrive at a Pok�mon Center where they are accused of trying to steal food. They find out that the center is run by Nurse Joy and her two daughters Marnie and Paige. After they clear things up, Ash, Dawn, and Brock decide to help the three. When Marnie needs to go deliver her dad's lunch to him at the Valley Windworks, Nurse Joy has Paige go feed the local pok�mon. Paige decides to show Ash her pok�mon friend Suicune! However, the legendary pok�mon is not at the lake it usually is. At the Windworks, the Marnie and Paige's dad uses his Ampharos to fend off a Team Rocket attack. However, the explosion causes the wires to be damaged and with a storm coming, the Pok�mon Center loses power. Nurse Joy decides to go to the Power Plant and figure out the problem. Paige then decides to go using Drifloon. They try to stop her, put the wind carries her, Pikachu, and Drifloon away! They head to the Power Plant and the power has been restored. Ash tells them about Paige and borrows Marnie's Drifloon to go after her. With the storm getting fiercer, will Ash be able to save Paige, or will Marnie be forced to call on an old friend to save her?
On the way to Eterna City, Ash and Dawn run into a TV crew who are recording local battles. Ash and Dawn decide to find a local pair of trainers who are on a winning streak and challenge them. They run into the trainers, named Ryan and Bryan and challenge them to a battle. The brothers agree as long as it is a tag battle. They agree and pit Turtwig and Piplup against Croconaw and Quilava. Soon Turtwig and Piplup end up attacking each other, leading to their defeat and a fight begins between them. After seeing the battle, Team Rocket steals Croconaw and Quilava. Now Ash and Dawn must help get them back so that they can have a rematch and show them their true strength, as well as redeem themselves.
Ash, Dawn, and Brock arrive in Eterna Forest where they immediately have to chase Aipom who is trying to get some Honey spread on a nearby tree. They meet the girl who spread the honey, Cheryl, who reveals that she was trying to capture a Burmy so she can find a special kind of honey called Enchanted Honey. She needs to capture a male Burmy, and she finally succeeds in doing so. Now she needs to evolve it into Mothim so that she can use it to find the honey. However, Team Rocket shows up and steals Burmy so that they can use Mothim�s power for themselves.
Ash, Dawn, Brock, and Cheryl continue to look for the Amber Castle so they can find some Enchanted Honey. While following Mothim, they run into a girl named Gardenia. After seeing Ash's Turtwig, Gardenia asks Ash for a battle. Ash agrees and he quickly thinks he has victory after she recalls Cherubi and is confident in Turtwig's speed. However, Gardenia's Turtwig is extremely fast and takes down both Turtwig and Staravia. Ash then realizes he must train even harder for the Eterna Gym. While they continue their search, Gardenia tells them to find a Combee to help them in their search. Before they can go find one, Team Rocket shows up to cause trouble.
Continuing their search for the Amber Castle, Ash, Dawn, Brock, and Cheryl chase after a Combee hoping it will bring them to a Combee Wall, and the Amber Castle. After losing Combee twice, they finally manage to come to a cliff which has tons of Combee Walls hovering in the valley below. The find a cave behind it and head into it. Also inside the cave, Team Rocket decides to start digging for some honey. This angers the Combee and they start attacking. Ash and the others arrive and confuse the Combee and send Team Rocket packing. After accidentally knocking down a Combee Wall, the finally find the Amber Castle. Inside they see the ruler, Vespiquen. Cheryl asks for some of the honey, but Team Rocket breaks in and start attacking. The army of Combee attack back and the ensuing battle threatens to destroy the castle.
On the way to Eterna City, Ash, Dawn, and Brock decide to stop and watch a Pokémon costume contest. They are extremely excited to watch it, and when they find out that the prize for winning the contest is a Pokémon egg, they decide to enter. Brock enters Croagunk as a Politoed, Dawn enters Piplup as a Weedle, and Ash enters Pikachu who will do impressions of other Pokémon. Meanwhile, Team Rocket is also entering the contest. As the first round gets underway, Ash, Brock, Jessie, and James all make it past, while Piplup accidentally uses Bubblebeam, making Dawn lose. As the final judging is about to begin, Jessie and Meowth decide to skip the contest and steal the Pokémon egg.
While heading for Eterna City, Ash and the others come across a trainer and his defeated Zigzagoon. He tells them that he was attacked by a wild Buziel that is incredibly strong. They decide to go after it so that one of them can capture them. At the river they encounter Zoey, who is looking for a Water-Type. They finally encounter the Buizel, but one by one, Piplup, Glameow, and Pikachu are all defeated. They then follow Buizel to its training ground and try the same training. At the same time they must also defeat Team Rocket, who want Buizel to themselves.
Ash and the others stop so that Dawn can introduce everyone to Buizel. However Buizel could care less. Ash decides to please Buizel by battling it with Turtwig, with the result of Turtwig being badly injured and taken to the Pokémon Center. There they meet an unexpected visitor in a member of the Sinnoh Elite 4: Lucian. Lucian tells them about the Champion League, a league you can enter after you beat regional leagues. Following the conversation, Buizel wants to battle with Lucian, and he accepts Buizel's offer. Lucian's choice of Pokémon is his Bronzong. However, Bronzong quickly defeats Buizel, damaging its fighting attitude, and worrying Dawn. Meanwhile Team Rocket plans to steal Bronzong and Buizel.
Ash, Dawn, and Brock finally arrive in Eterna City. They head to the museum where the rare Adamant Orb has been stolen by thieves. They soon run into both Gardenia and Nando. Since the thieves used a Sunflora to help rob the museum, they believe Nando and his new Sunflora are the thieves. Ash, Dawn, and Brock send out their Pokémon to try and catch the real thieves, and they even have help from Viridian City's Officer Jenny. The poilce officers then begin their search for Nando's Sunflora, who has just run into Pikachu and Piplup. Meanwhile, Team Rocket, who are the real thieves, hideout is a small room since the entire museum is sealed off, but they are soon found by Pikachu, Piplup, and Sunflora.
The day finally arrives where Ash will challenge Gardenia for his second Sinnoh Badge. As the battle begins Gardenia and her Cherubi seem to have the upper-hand while using the weather to their advantage. Ash brings out Staravia and scores an early win, but can he repeat the success when Gardenia chooses Turtwig and whatever Pokémon she has in store? Meanwhile, Team Rocket try to sneak into the gym to get Pikachu but end up in a underground filled with treasure.
After leaving Eterna City, Ash, Dawn, and Brock travel down Cycling Road to Hearthome City, the location of the next gym and contest. Soon Brock's egg begins to glow, so they head to a nearby Pokémon center. Then they get there it seems to be abandoned. However, Nurse Joy and Chansey are there, but Nurse Joy acts extremely sad since her center has looked like a dumped ever since Cycling Road was built, and she thinks she is no longer needed since no one stops by. They try to cheer her up (as well as eventually help her restore the center), since they need her to help with Brock's egg. In the center, the egg finally hatches into Happiny. Brock and Happiny instantly take a liking to each other, and Brock gives her a bath and starts to work on a stone for her to hold. Meanwhile, Team Rocket is lurking around the center and plan to steal Happiny so they can evolve it into Chansey and run their own hospital and become rich.
Continuing on their way to Hearthome City, Ash and the others come across a giant river. They discover there is a steamboat they can take that will bring them to a location near Hearthome City. They go on the boat and let their Pokémon out to enjoy it. Ash, Dawn, and Brock decide to go shopping before the ship leaves, and they leave Pikachu and Piplup in charge. While they are at the store, Pachirisu accidentally falls on the ships control and the ship begins to set sail! To make matters worse, Team Rocket is on the ship with all the Pokémon ready to be stolen.
On the way to Hearthome City, Ash, Dawn, and Brock stop at a Pokémon center. On the TV they watch a battle between Lucian and the Sinnoh Champion: Cynthia. When Ash hears that Cynthia is in nearby Amity Square, he rushes off to meet her. When they arrive at the square, Paul is also there and challenges her to battle. Cynthia agrees and the two begin their battle. However, Paul soon losses four of his Pokémon to Cynthia's powerful Garchomp and calls off the battle. He takes his Pokémon to the Pokémon Center where Cynthia then heals them. Meanwhile, Ash might learn more about Paul and how he treats his Pokémon, while Team Rocket plan to steal Paul's Pokémon.
Continuing their journey to Hearthome City, Ash and friends are traveling through the woods when a worried Glameow and Misdreavus come over to them. They follow the pair and find Zoey, who has sprained her foot. They help her back to her camp when she introduces them to her new Shellos. Zoey also reveals that in the Hearthome Contest, trainers not only have to use two Pokémon in the battle rounds, but in the appeal round too! Zoey then offers to help Dawn in her training, as well as demonstrating her combination. Meanwhile, Jessie takes a break from catching Pikachu in order to show the two coordinators up.
On the way to Hearthome City, Ash, Dawn, and Brock stop by a scenic lake to relax and let their Pokémon out. While relaxing, an Electrike comes running by and accidentally attack them, and shocking Ash. Electrike's trainer, Jaco, comes over to apologizes. Jaco tells them that he is a breeder. They a man comes over to Jaco and tells Ash and the others of the Training Center for electric Pokémon that is nearby. While there, Jaco confesses that he would rather breed flying-types, but he is stuck in the center raising an Electrike that he does not have faith in. However, Brock does convince him to let him help take care of Electrike for a little while. Meanwhile, Team Rocket see the dedication that Electrike is putting forth, which inspires James and Meowth to help, while Jessie decides to capture it.
Continuing their journey to Hearthome City, Ash, Dawn, and Brock become lost in the woods. When it starts to rain, they head under an old gate to stay dry. They notice that on the other side it is not raining so they continuing walking. They finally arrive at the Pokémon center, where Professor Oak and Johanna are. They tell Ash and Dawn of the playoffs being held to determine the worlds greatest trainer and coordinator and tell them to compete. The two agree, and end up facing Cynthia and Johanna! Although it seems they will lose, both of them prevail. Even more strange, all the Nurse Joys and Officer Jenny's suddenly love Brock, Jessie becomes a TV Star, James find tons of rare bottle caps and Giovanni finally wants Meowth instead of Persian. However, this may just be one big illusion.
Continuing the journey to Hearthome City, Ash, Dawn, and Brock stop to eat lunch. After eating Turtwig brings them to a cliff where a Hippopotas is stuck on the cliff. After helping it, the Sinnoh Now staff shows up and tells them they were filming it and it accidentally got lost from its family. They decide to help the Pokémon get back to its family, and must do it before Team Rocket captures the easily tricked Pokémon.
Continuing their journey to Hearthome City, Ash, Dawn, and Brock comes across the rare Pokémon Shieldon. Before they can marvel at the rare Pokémon, Hunter J and her minions return, and they want Shieldon! While battling her minions, they run into Gary! They hold J off long enough for them to get away. They then plan to meet up with Professor Rowan. Meanwhile, Team Rocket decide to sneak aboard J's ship to "teach" her a lesson. J then has her minions surround they area where Ash's group is, but they manage to find a way out. J then corners them and attacks. Despite Ash battling his hardest, J manages to get one of the Shieldon. Ash and Gary then sneak aboard J's ship to get it back.
Continuing the journey to Hearthome City, Dawn decides to make a pit stop at a local Pokémon center in order to get a new PokeTch function. However, Nurse Joy then reveals that the center giving it out is on the other side of the woods, so Dawn heads there. On the way, Team Rocket intercept them and drag them into a cave to take a picture with their pokemon. Before that can happen a group of rock Pokémon roll throw, causing them to all run. Ash, Dawn, and Brock wind up separated from each other in a maze. To makes matters worse, some of the Pokémon are lost too. While they try to find each other in the maze, Team Rocket tries to keep them separate so they can catch all of their Pokémon.
Ash and friends have almost arrived at Hearthome City. Before they can continue their journey, a girl named Mira appears and says she will teleport them to Hearthome City. However, she ends up teleporting them to a nearby lake and asks Ash, Dawn, and Brock to help her retrieve her Grandma's pendant from the sunken town. When they get attacked by a Gyarados, Mira finally tells them the whole story. The so called pendant is actually a pokeball with one of Mira's old pokemon in it - a Sandshrew. After seeing how much Mira cares for it, the three decide to help her despite the lies she has been telling.
A clip show summarizing the important events of the first 47 Diamond and Pearl episodes, including Ash's victories over Roark and Gardenia and the introductions of new rivals Paul and Zoey.
Ash heads for the Hearthome Gym for his battle, only to find out that the gym is closed. Nando then tells them about the Hearthome Tag Battle Tournament, which they decide to compete in. Before that happens, Dawn must compete in the pokemon contest. The contest won't be as easy as she thinks, not only must she pull off a double performance, but do so while competing with Jessie, Zoey, and Nando. All four of them pull off great opening appeals, but when the Final 8 are selected, Dawn is not one of them. She is crushed at the loss and leaves to be alone. The final round then comes down to Zoey and Nando, but who will achieve victory?
Taking Nando's advice, Ash and Brock decide to enter the Hearthome Tag Battle Tournament. In order to cheer her up following her contest loss, Ash also enters Dawn in the tournament. As everyone is paired up with their partners, Ash finds out that his partner will be none other then Paul! Things are just a strange for Dawn due to her partner, Conway, being a little to attached to her. Meanwhile, Brock gets lucky when he is paired with the beautiful Holly. As the tournament begins, Dawn and Conway, and Brock and Holly manage to pull off wins, but can Ash and Paul set aside their differences and work together?
Ash and Paul, Dawn and Conway, and Brock and Holly have all made it to the next round of the Tag Battle Tournament. Due to the big crowds at the Pokémon center, Brock helps Nurse Joy out, while Dawn and Conway try to figure out strategies for the upcoming matches. Meanwhile, Paul is training Chimchar and is forcing it to battle Torterra, Ursaring, Murkrow, and Elekid all at once. When Ash and Dawn find out they are angered. Things go so far that even Nurse Joy intervenes to help Chimchar. After heading back to the center, Paul finally reveals why he trains Chimchar so hard.
Following Paul releasing Chimchar, Ash offers it to join his team. Delighted, Chimchar joins Ash. The next day the final rounds of the Tag Battle Tournament begin. Dawn and Conway beat their opponents, while Brock and Holly go up against Ash and Paul. Paul refuses to work properly with Ash and quickly ends the battle, even at the risk of knocking Ash's Staravia out. The final round then begins, with Ash choosing to use his new Chimchar. Despite their lack of cooperation, Ash and Paul manage to barely work together in the battle between Dawn and Conway. With Chimchar under a new trainer, and Ash facing a team that has the advantage, who will win the tournament?