Once again Ash sets his sights on a new region and a new adventure. Continuing his journey alone, Ash arrives in the beautiful Unova region with just Pikachu at this side. While on his way to visit Professor Juniper, Unova's resident professor, a mysterious shadow appears above and Pikachu loses the ability to use his electric attacks. Ash also encounters a trainer named Trip and the two decide to have an unlikely ending battle.
With Pikachu healed up, Ash decides to not return with his mom and Professor Oak to Kanto and to travel around the Unova region instead. As he begins his travels he meets a girl named Iris and together they decide to travel with each other, but when Pikachu and Axew are stolen by Team Rocket, will they be able to save their only Pokémon?
After learning that the first gym of Unova is located in Striaton City, Ash and Iris begin their journey there. However, they are stopped by a boy who requests their help. A group of Sandile are terrorizing his sand bath resort and he wants Ash and Iris's help to stop them.
While on the way to Striaton City, Ash and Iris arrive in Karakusa Town and Ash hears about a place called the Pokémon Battle Club. Interested, he decides to go check it out. However, trouble is abound as a mysterious pokémon has been spotted nearby and both Ash and Iris wants to capture it.
Ash and Iris arrive in Striaton City, the location of Unova's first gym. When they arrive in town they meet a boy named Cilan who says he is a Pokémon Sommelier, someone who is able to test the compatibility between a Pokémon and trainer. He leads them to the Gym where it is revealed that he and his two brothers are all the Gym Leaders of Striaton City. Will Ash be able to defeat the three brothers and win his first badge?
Ash is taking a break at the Pokémon Center following his Gym Battle when all of a sudden Iris comes dashing in. Apparently Axew has fallen asleep and will not wake up. Overhearing, a professor named Fennel and her Munna come to help them.
While on the way to the next Gym, Ash, Iris, and Cilan stop to take a break. While eating a Snivy comes by and starts eating their food. They try to stop it but it uses Attract to stun Pikachu and cause other mischief. What will they do to stop it.
While stopping for lunch by a river, Pikachu and Axew's food suddenly goes missing. Everyone begins to search around and they find a Darumaka eating the food. They give chase but lose it and get lost.
On the way to Nacrene City, Axew wanders off to get some apples and ends up trapped in the horms of the bug pokémon Scolipede. The Pokémon begins rampaging and now everyone must find a way to stop it and get Axew back.
On the way to the next city Ash and his friends run into Trip again. Determined to prove that his previous loss was just a fluke, Ash challenges him to a battle. Trip accepts and the two get ready to have a five-on-five battle.
On the way to Nacrene City, Ash and friends encounter the Pokémon Dwebble. However, this Dwebble does not have a rock on its back as it should. It begins to make a new shell, but then three more Dwebble show up and trouble starts.
Ash and friends are continuing their journey when a group of kids suddenly appear in front of them. They begin throwing mud balls at Ash and his friends and as they run off, a Trubbish steals Ash's hat. They then give chase.
Ash and friends meet a girl named Bianca. Professor Juniper has asked Bianca to meet up with them in order to deliver a badge case to Ash. As Bianca gets the case out it is all dusty from sitting at the bottom of her bag. Suddenly a Minccino comes by and snatches the case and runs off with it. Ash and friends give chase.
Ash, Iris, and Cilan finally arrive at Nacrene City, the location of Unova's second gym. When they arrive at the gym, which is located in the city's museum, the door is locked. They soon find out that some strange things have been happening in the museum. Ash, determined to have his gym battle, decides to head inside and find out what is happening.
With their museum adventure behind them, Ash finally gets to challenge the Nacrene City Gym Leader, Lenora. Lenora specializes in Normal-type Pokémon and is no pushover. Will Ash be able to defeat Lenora and earn his second badge?
After his devastating loss against Lenora, Ash heads to the Nacrene City Battle Club to train for a rematch. While at the Battle Club, his training proves useful for both Oshawott and Tepig. With renewed confidence, Ash heads back to the gym to battle Lenora yet again. Will he defeat Lenora and win his second badge?
The day everyone has been waiting for has arrived! Ash's egg finally hatches, and it hatches into a Scraggy! However, the celebration ends when Scraggy proves to be a little troublemaker, and soon puts Ash and friends in danger with some wild Pokémon.
Continuing their journey, Ash and friends reach Pinwheel Forest. There Ash sets his sights on catching a Sewaddle after encountering one. However, this Sewaddle is not careful and winds up in some dangerous situations. Meanwhile, Ash and friends also receive help with Sewaddle from Castelia City Gym Leader Burgh.
Continuing their journey, Ash and friends come across an authorized Pokémon Connoisseurer. The Connoisseurer is at a new store performing readings for people and their Pokémon. They decide to go watch them so that Ash can get a free reading and Cilan can see another Connoisseurer in action. However, this Connoisseurer has a connection to Cilan.
While Ash is doing some training with his Scraggy, he and his friends are confronted by the same Sandile they met near Nuvema Town. Ash, wanting to accept Sandile's challenge is interrupted by three Ducklett which quickly snatch Ash's hat and Sandile's sunglasses.
Ash, Iris, and Cilan arrive at the famous Skyarrow Bridge, their last obstacle before reaching Castelia City. They try crossing the bridge, but a Gothitelle appears and prevents them from crossing. They must now find a way to get past it and get into the city.
Ash and friends have finally arrived in Castelia City. While exploring the city they run into Burgh. After hearing a noise underground, they go to find out what it was and find a wild Venipede. It is injured, and even though they heal it, the other Venipede in the sewers become upset and begin attacking the city above. Now Ash and friends must help to stop them.
The time has arrived, Ash is finally going to battle Burgh to try and win his third badge in Unova. Burgh is an excellent Bug-type trainer with many tricks up his sleeve. Will Ash be able to win his third badge?
Ash, Iris, Cilan and Bianca are on their way to Nimbasa City. Axew encounters an Emolga that had just stolen a bunch of apples from a group of Patrat.
Iris decides to do some training with her new Emolga. However, while training it is discovered that it has a problem. Whenever Emolga uses Volt Switch, instead of switching places with one of Iris's other Pokémon, it also switches places with Ash and Cilan's Pokémon as well!
Continuing to Nimbasa City, Ash and friends suddenly find themselves caught in the rain. They notice a mansion nearby and go inside hoping to seek shelter from the rain. However, things are not as they seem. Soon a group of Litwick begin tormenting them and cause havoc.
While on the way to Nimbassa City, Ash and friends encounter a trainer who is skilled in training Dragon-type Pokémon. Iris, determined to achieve her goal given to her by the elder of her town, seeks the wisdom of the trainer, hoping to make Axew stronger.
On the way to Nimbasa City, Ash meets a Pokémon trainer and the two decide to battle. During the battle Oshawott's scalchop is kicked away from Oshawott and becomes lost in the woods. Devastated, Oshawott frantically searches for it, and eventually a replacement for it.
While on the way to Nimbasa City, Ash and friend encounter a group of Cottonee. One of these Cottonee is in love with another one, but she rejects him, so Cilan decides to help the Pokémon win her love.
Continuing their journey to Nimbasa City, Ash and friends are suddenly woken up in the middle of the night by a mysterious light. Soon after they encounter a professor and the mysterious Pokémon Elgyem.
Continuing their journey to Nimbasa City, Ash and friends stop to have lunch. However, they end up ruining Cilan's lunch. Soon after Ash and Iris wander off and run into Trip. After seeing Trip's new Pokémon Ash is eager to battle and Trip agrees to a three one three battle. Who will win?
While taking a break on their journey, Ash and friends come under attack by wild Pokémon and the gang's Pokemon are badly poisoned. The only thing nearby that can heal them are herbs found at the bottom of a nearby lake. However, when Oshawott goes to get them, it is attacked by a wild Palpitoad and Stunfisk. Now everyone must find a way to stop the two Pokémon and heal the gang's Pokemon.
On their way to Nimbasa City, a girl confronts Iris and demands a battle against her and Axew. She says she is a Dragon Buster and it is her job to defeat Dragon Trainers. Due to his lack of experience Axew falls easily and in a fit of rage, Iris calls out Excadrill. Excadrill still ignores Iris and too is defeated. Following the battle Iris finally reveals what happened to her and Excadrill and decides it is time to finally get him to listen to her.
On their way to Nimbasa City, Ash and friends come across a group of Roggenrola who are being targeted by Team Rocket. When Team Rocket reveals their plan for the Pokémon they decide to stop them and save the Pokémon.
Ash and friends arrive in a town where the pokémon Audino is popular among the residents. However, the Audino have been mysteriously disappearing and acting strangely. Cilan decides to help Officer Jenny get to the bottom of this strange case.
Ash, Iris, and Cilan meet up with Professor Juniper and Fennel who reveal they are going to revive a Pokémon fossil. the fossil is the pokémon Archen. Archen is a wild pokémon that likes to do as it pleases, but it cannot fly. Ash and friend decide to help it learn to fly. Meanwhile, Team Rocket also set their sites on the pokémon.
Continuing to Nimbasa City, Ash and the gang decide to take a rest stop in a town. They run into Bianca who presents a fishing competition poster, unknowingly staged by Team Rocket. Cilan decides to enter the fishing contest. Meanwhile Team Rocket plans to steal the Pokemon the contestants caught.
Continuing to Nimbasa City, Ash and friend encounter a boy who directs movies. The boy is having troubles with both his lead actress and his pokémon Zorua. Ash and friends agree to help him with his movie.
Ash and friends arrive in Nimbasa Town where they learn of a tournament that is to be held. They decide to enter it before they leave town. However, they have stiff competition as trainers they've encountered in Unova also gather for the tournament.
The next round of the Club Battle tournament begins with a battle between Cilan and Trip. Meanwhile, Ash, Iris, and Bianca wait in the wings for their upcoming battles. Who will progress to the next round?
The Club Battle tournament continues with Ash and Georgia's battle ending. Next up is Cilan vs Luke and Iris vs Stephan. With tough opponents ahead of them will Cilan and Iris continue to advance in the tournament?
The Club Battle semi-finals conclude with Ash and Iris as the victors. Now the two friends are set to go head to head in the tournament finale. Who will be crowned the victor?
On the way to Nimbasa City, Ash and friends find Meowth of Team Rocket lying in a bush. Meowth says he botched a Team Rocket operation and was fired and disowned. He then joins Ash, Iris, and Cilan. Meanwhile a Scrafty comes by and kidnaps Axew.
While continuing to Nimbasa City, Ash and friends come across a Purrloin. Meowth and Oshawott fall for the little pokémon and soon begin to follow whatever it says. However, Cilan doesn't trust Purrloin and follows everyone reluctantly.
On the way to Nimbasa City, Ash and friends encounter a Beheeyem. After discovering it's secret ability, they decide to try and test it out. Meanwhile, Officer Jenny shows up and reveals that she is investigating the Beheeyem.
While on the way to Nimbasa City, Ash and friends come across a Cubchoo that has been separated from its pack. They decide to help find the pack, but that proves difficult when another group of Beartic constantly attacks them.
Ash and friend finally arrive in Nimbasa City. Before heading to gym they decide to check out the Battle Subway. However, a mysterious event causes the Subway System to halt. They head to the Pokmon Center where strange events begin...
Meowth has betrayed the group and all their Pokémon have been captured as Team Rocket use the Subway to get away.