As the menace of Team Galactic continues to loom over the Sinnoh region, Ash and Dawn keep getting caught up in the schemes of this mysterious group of villains—as well as facing some other unexpected challenges! Dawn’s got her hands full dealing with the many problems of her Pokémon, while Ash’s ongoing rivalry with Paul finally comes to a head in a full 6-on-6 battle! It might be the ultimate test of training styles—will our heroes come out on top?
Ash contacts Professor Oak who tells them about a hotel in the city that serves a delicious dessert. They head to the hotel, but it is closed. As they turn to leave the door mysteriously opens. They then head inside where they are attacked by a Rotom.
While awaiting the return of the Canalave Gym Leader, Ash decides to train. Dawn also decides to begin training her newly evolved Piloswine for its contest debut. However, Piloswine begins to ignore Dawn. Trying to reconnect with it, Dawn enrolls in a "Pokémon Friendship School".
Roark, the Oreburgh Gym Leader, and son of Byron, the Canalave Gym Leader, is visiting his father. The two of them, both users of Fossil Pokémon, are having an argument about who likes them more; and they end up battling. Meanwhile, Ash has returned to the Canalave Gym for a Gym Battle after hearing that Byron is back.
Ash finally gets to battle the Canalave City Gym Leader, Byron. In the first round Byron chooses his Bronzor, while Ash uses Chimchar. Ash tries to use Chimchar's type-advantage to score an early victory, but this begins to prove ineffective when he learns that Byron has a defensive style of battling.
Ash and friends are having lunch when all of a sudden a Luxio comes along and steals all of their food. They follow it into the sewers where they discover a Wailmer that is trapped in the sewer and can't make it back to the ocean.
Everyone is getting prepared to leave Canalave City to head to Dawn's next contest. Before they leave, Ash calls Barry to tell him of his win at the Canalave Gym. Barry is at Iron Island, and something is currently wrong with his Empoleon. Ash, Dawn, and Brock head to Iron Island to see him, but all of the steel pokémon are going crazy. A man named Riley appears and helps them, and they decide to find the source of the problem.
Ash, Dawn, and Brock, along with their new friend Riley search for the source of the mysterious waves affecting the Steel Pokémon, and find Team Galactic. What is Team Galactic's plan, and what do they want with the ruins on Iron Island?
Ash and friends decide to take a boat to the location of the next contest. On the ride Team Rocket appear and steal Pikachu and Piplup. They manage to escape but they wind up on a deserted island. Will they be able to make it back to their trainers?
Ash and friends arrive in the town where Dawn will enter her next Pokémon Contest. They find out that a lot of people have come to the town in order to see the legendary Pokémon Phione, who lives in the surrounding sea. Legend has it that anyone who sees Phione will have good luck, so Dawn decides to try and catch a glimpse of it.
Dawn is getting ready to participate in her next contest. She meets a girl with a Gabite who is not so friendly. She believes that Dawn's victory in the Wallace Cup was pure luck and is determined to defeat Dawn. Dawn is now determined to defeat her and prove that her win was not just luck.
Ash and friends arrive in a town where an Officer Jenny and her Chatot are working hard to find Team Rocket and arrest them. Jenny wants Ash and friends to help.
Ash and friends are lost in a blizzard when they run into a Froslass. Froslass leads the trainers to a small lodge, where it provides them with warm soup and a bath. But is it as friendly as it seems?
After yet another failed attempt to steal Ash's Pikachu, Team Rocket wind up at a Ramen shop. Jessie and James are surprised when they discover that the shop owner was one of their underclassmen from their days at the Team Rocket training facility.
On the way to Snowpoint City, Ash and friends stop in a town where a PokéRinger competition is to be held. Ash is eager to participate in the contest with Staravia. However, he soon finds out that Paul is also entering with his Honchkrow.
On the way to the next town, Ash and friends decide to stop and take a break. Dawn heads to a river to fill up her canteen, but is attacked by a wild Aggron and falls into the river. She manages to get out of the river far down stream, and is now lost from Ash and Brock. Aggron returns and after calling out Mamoswine, it is badly hurt. Now, Dawn must take care of Mamoswine by herself, and hide from Team Rocket and Aggron at the same time.
On the way to Snowpoint City, Ash and friends suddenly find themselves stuck in a bunch of traps. Soon a Snover pops out of the bushes. It's is very playful and wants to be with someone. Team Rocket, however, want to steal Snover for themselves.
On the way to Dawn's next contest, Piplup suddenly begins to show signs of evolving. When they arrive at the next Pokémon Center, Kenny and Barry are there as well. Dawn and Piplup must decide whether or not to have Piplup evolve into Prinplup, while trying to fend off Team Rocket who want to capture Dawn's Piplup, Kenny's Prinplup, and Barry's Empoleon to have a complete evolutionary set.
Ash and friends have arrived at the location of Dawn's next Pokémon Contest. With only one more ribbon needed to enter the Grand Festival, she is extremely excited. With both Jessie and Kenny entering the contest, however, will Dawn be able to pull off a win?
After learning about a Pokemon Ping Pong Tournament from Barry, Dawn decides to enter. The previous champion sees them preparing and notes that Dawn is a shoe-in for victory with her Ambipom, who seems to have a natural talent for the game.
Ash and friends stop in a town on the way to Snowpoint City. There they meet a girl who only likes cute Pokémon. After she insults Dawn's Piplup, Dawn challenges her to a battle.
Ash and friends finally arrive in Snowpoint City. They are welcomed by the Gym Leader, Candice. She offers to show them around town. She brings them to a trainer's school where she is a teacher.
Ash finally arrives at Snowpoint Gym for his battle with Candice. This gym will be different from his previous gym challenges, with each trainer using 4 pokémon each. Can Ash defeat Candice and win his seventh badge?
At the Snowpoint City Pokémon Center, Ash and friends run into Paul, who has come to town to challenge Candice. Surprisingly Paul's brother Reggie also arrives at the center. To add to the surprises, Pyramid King Brandon arrives in Snowpoint City. After Ash and Reggie talk about their great battles in Kanto, Paul becomes upset and challenges Brandon to a battle.
Pokémon Hunter J arrives in Snowpoint City and targets the legendary Pokémon Regigigas, which is sleeping inside the Snowpoint Temple. After J commands her henchmen to launch an attack, a maiden from the shrine asks Ash and his friends for help. But Ash and the others come too late; Regigigas has been reawakened and starts rampaging.
While on a train heading to Lake Acuity, Ash and his friends meet Looker; an International Police Officer who is currently tracking Team Galactic.
Ash and friends arrive at Lake Acuity, the site where Ash and Paul will have their full 6-vs-6 battle. After healing his Pokémon, Ash meets up with Paul and the two begin their long awaited battle. Who will ultimately be victorious?
Ash and Paul continue their 6-on-6 battle. With both teams fighting extremely hard it could be anyone's match, so Paul calls out his newly evolved Magmortar, hoping it will secure him victory.
With all of his Pokémon weak and injured from the battle with Paul, Ash rushes to the Pokémon Center in order to get them healed. Nurse Joy does not, however, have the berry needed to properly heal Monferno. Brock decides to help and heads to Lake Acuity to find it. While at the lake, something strange happens....
Dawn decides to start training for the next Pokemon Contest with Mamoswine. However, despite overcoming its disobedience, Mamoswine still won't battle. Things turn bad when Mamoswine runs into a forest and Dawn chases after it.
Dawn's favorite television show, Pokémon Hustle, is searching for actors near their current locations, and Dawn decides to try out for the show. Ash and Brock decide to try out, as well.
Ash and friends are on their way to the town where Dawn's next contest will be held. They arrive at Mt. Coronet, the massive mountain that divides the Sinnoh region in half. The mountain also divides the region's pokémon, like Shellos. The Blue and Pink Shellos have ended up on the opposite side of the mountain, and while trying to figure out why, Piplup falls into an artificial tunnel, and when they go to rescue him, they come across something sinister.
While on the way to Twinleaf Town, Piplup falls in love with a Marill. However, an Elekid also has its sights on Marill. What will become of this love triangle, especially when Team Rocket show up?
Ash and friends go to Dawn's hometown of Twinleaf. Upon arrival, they find that they made it in time for the Twinleaf Town Festival, where a Pokémon Contest is about to be held. Dawn decides to enter, and it isn't long before she finds herself facing none other than her mother, Johanna, in battle. Knowing that Johanna won the Grand Festival in the past, will Dawn be able to defeat her?
As the Twinleaf Town Festival continues, Ash and friends are surprised when they find that one of the upcoming Pokémon courses is to be hosted by none other than Professor Oak. Trouble starts brewing, however, when James brings back an old plan: to disguise himself as the professor.
Ash and friends are still enjoying the Twinleaf Festival when they run into Barry. Wanting to see how the other one has improved, Ash and Barry decide to have a battle. However, plans are put on hold when the mysterious Xatu appears out of nowhere.
Ash and friends find out that the main event for the Twinleaf Town Festival is a battle tournament, and the winner gets to have a battle with the Sinnoh Battle Frontier Brain, Palmer. Excited about that, Ash enters the tournament with hopes of battling him.
The Twinleaf Town Festival has concluded, and Ash and friends continue their journey to the town hosting Dawn's next Pokémon Contest. The three soon fall into yet another one of Team Rocket's traps. However, things are not what they seem. A mischievous Togepi stirs up trouble for everyone and in the end they must work together in order to stop Togepi.
Ash and friends arrive at a festival promoting the Johto region where they meet two trainers from the Johto Region and their starters, Chikorita and Totodile. At the festival, Dawn and the girl have a battle over a Pokémon egg. However, Team Rocket also has their eyes on the egg.
The two Johto trainers decide to join Ash, Dawn, and Brock on their journey. While on the way to Dawn's next contest, the group stops near the Valley Windworks for Dawn to do some training. When Marill goes missing, the group heads into the windworks to find it, but once inside they are attacked by wild Pokémon and become trapped. Will they be able to escape the building?
While on the way to the Dawn's contest, Ash and friends encounter a wild Gible, a very rare Dragon-Type Pokémon. Ash and Kazunari are both interested in capturing one, and they both go after it. Who will catch Gible?
The time for the Lilypad Pokémon Contest has finally arrived. Dawn is excited for the contest since she still only needs one more ribbon in order to get into the Grand Festival. Meanwhile, when Jessie gets sick, James takes her place in the contest. Who will win the contest?
Following the pokémon contest, Ash and friends decide to take a break. While they rest, they decide to have a tag battle since Lyra and Khoury have to return to Johto soon. However, before that happens Team Rocket shows up and steals Pikachu and Piplup, putting their plans on hold.
Still on the way to Sunyshore City so Ash can battle for his final Sinnoh Gym Badge, Ash and friends meet a female trainer and her Misdreavus who are battling a Murkrow for a Dusk Stone, which has the power to evolve Misdreavus into Mismagius. It also has the power to evolve Murkrow into Honchkrow, so she is frantic to get the stone.
On the way to Sunyshore City, Ash and friends stop in a forest. Things start to get chaotic, however, as Pikachu gets upset with Piplup in a debate over which of them Ash likes best. However, a mysterious wave all of a sudden makes the two Pokémon inseparable, so Ash and the others must solve the problem.
On the way to Sunyshore City, Ash and friends are walking through a grassland and come across Meowth of Team Rocket, who is injured. When they ask him what happened while treating his wounds, Meowth says that he was attacked by Team Galactic in a large building called the Fuego Ironworks. Not only that, Jessie, James, and even Looker of the International Police have been captured. Upon hearing this, Ash and the others decide to head to the Fuego Ironworks to save them.
Team Galactic has almost achieved its ultimate goal. In order to complete their plan, Cyrus hires Pokémon Hunter J to catch the legendary Lake Guardians, Azelf, Uxie, and Mesprit. Will J and Team Galactic succeed, or will Ash and friends put a stop to their plans?
Cyrus has succeeded in his goal of awakening Dialga and Palkia and now the entire Sinnoh region is in danger. Cyrus plans to rebuild the world in his image, but that means the destruction of everything. Can Ash, Dawn, Brock, Looker, and Cynthia stop Team Galactic and save Sinnoh?
With only one more badge needed to enter the Sinnoh League, Ash and friends resume their journey to Sunyshore City. Meanwhile, James stumbles upon a treasure chest that holds a big secret.
While on the way to Sunyshore City, Ash and friends meet a master of air battles. Hoping to improve Gliscor's flying, Ash decides to have a battle with him, and the results may be more than he expected.
Knowing that the next contest is going to be a double performance, Dawn begins training Mamoswine and Cyndaquil. Zoey arrives and decides to help Dawn with her training.
On the way to Dawn's next Pokémon Contest, Ash and friends come across a wild Gible. Gible is determined to learn the powerful move Draco Meteor, so Ash decides to help by doing some special training with it.
Ash and friends continue on their way to the next town when they notice that the Gible they helped has been following them. Ash decides to try and catch it, but Barry shows up and wants to catch it too. Now the two trainers race to capture it first.