Still in Kanto, the group heads to Cerulean City to teach the Alola group about Pokémon Gyms. Having had his last match at Cerulean Gym interrupted, Ash is eager to have a proper match as demonstration, and Kiawe also wants to battle. As such, battles soon begin of Ash VS Misty and Kiawe VS Brock, but when they start to use their Z-Moves, Brock & Misty pull out their trump cards: Mega Evolution. Will Ash manage to push through the Mega Gyarados' strength with his Z-Move?

As part of an extra curricular class, the group travel to Kanto. When there, Ash meets up with his old friends Brock and Misty. Then, when takingthem through Oak's Laboratory to meet his old Pokémon, the group gets losts. To make matters worse, Team Rocket have also returned to Kanto briefly and have their eyes set on the Pokémon in the laboratory once again. Will they succeed?

Charjabug Races are very popular in Alola and Sophocles is a huge fan. Wanting to enter with his Charjabug, Sophocles recruits Ash and Kiawe to team up with him to enter a race, but his Charjabug seems very docile and doesn't move fast in the car. Wih lots of training done, when the day of the race comes, it proves to be tough for Sophocles. Would he be able to win?

Despite her recently obtained Z-Ring and Waterium Z, Lana is still having difficulty mastering Z-Moves. However, she soon meets a trainer with Popplio's evolution, Brionne, who has mastered the Water Z Move. Lana asks for their help and learns that they are around hunting for sunken treasure, and they start training together. When they receive information about the treasure, they learn it is protected by a Dhelmise. Will they be able to obtain it and master the Z-Move?

With their cafeteria appearing on TV, Mallow ends up having a fight with her father and storming off into the forest. However, she soon finds herself injured and has to be protected by a wild Oranguru. However, Steenee has gone into the forest to look for Mallow only to find Team Rocket in pursuit. Will they be able to reunite?

After another unsuccessful attempt to defeat Ash, Team Rocket are blasted off again. However, for the first time since they arrived in Alola, Bewear didn't protect them, causing Jessie and Mimikyu to end up in the shopping mall, causing Mimikyu's disguise to tear. With Mimikyu's true nature bringing terrible consequences, Jessie tries to provide alternatives, but Mimikyu is opposed. How will Jessie help Mimikyu?

Following the Grand Trial, Rockruff continues to get agitated and restless and decides to go out in the night. Not returning in the morning, Ash & co. start looking for it. Olivia suggests Ash check the Ruins of Life, where he eventually finds Rockruff. Learning it faced off against Tapu Lele, Rockruff is highly injured and, before they know it, it starts to evolve...

It's time for the Grand Trial on Akala Island. Ash has challenged Olivia and the battle is a Double Battle. With Ash using Rockruff and Rowlet, he soon finds that something is up with Rockruff and it's not acting right. Due to this, Olivia's Lycanroc and Nosepass put Ash into a tough position. Will Ash and Rockruff be able to push through?

Lychee and Professor Kukui send the class out to find ingredients for Akalan Curry in groups of two. The team of Satoshi and Mao find their task more challenging than expected, especially in getting past angry Karikiris, an Alolan Parasect and an Alolan Digda. Their search for the final ingredient brings them face-to-face with a Totem Rarantesu. Satoshi and his Pokémon must now battle Rarantesu and its partner Powalen, but there may be more to this than meets the eye.

Satoshi and his friends go to the Wela Volcano Festival, where an Alolan Garagara appears and takes the "Wela Crown", which supposedly has the power to make Pokémon stronger. Satoshi and Kaki chase after it, which leads to a fierce battle between Garagara and Kaki's Bakugames in which, even when using a Z-move, Bakugames is defeated. Kaki is devastated and disheartened by the loss, but Satoshi and Bakugames encourage him. The next day, Kaki and Bakugames face Garagara in a rematch, but this time Bakugames wins. Garagara not only returns the crown but also decides to join Kaki as one of his Pokémon. Garagara develops a rivalry with Bakugames in the process.

Ash Ketchum wakes up late one morning after having broken his alarm clock in his sleep. He eventually makes it to Professor Oak's lab, but he (even though he wants Bulbasaur, Charmander, or Squirtle) is told by Professor Oak that the three starter Pokémon (Bulbasaur, Squirtle, and Charmander) have already been taken by Trainers who were on time. However, Oak reveals that he has one more Pokémon, an Electric-type named Pikachu. Ash has no choice but to take a naughty Pikachu. Despite its volatile and feisty personality, as well as its refusal to get inside a Poké Ball, Ash happily takes Pikachu for his journey.

Outside of Pallet Town, Ash encounters a Pidgey. When Pikachu refuses to fight it, Ash tosses a rock at it, but it hits a Spearow that mistakes Pikachu as the culprit. Soon, more Spearow show up forcing Ash and Pikachu to run. Injured and tired, Ash tells Pikachu to get inside its Ball, but it once again refuses. Instead, Pikachu defends Ash from the Spearow by summoning a large Thunderbolt that scares them away. As the storm ceases, Ho-Oh flies above and drops a feather called a Rainbow Wing. Ash and Pikachu decide to go and find the Legendary Pokémon.

After hearing the Legendary Pokémon Entei is nearby, Ash and several other Trainers rush into the woods to look for it. Ash finds the Entei, but ends up fighting over it with a Trainer named Verity and an aspiring young Pokémon Professor named Sorrel. When Entei escapes, Ash and Verity get into an argument and Sorrel leaves, telling them that they need to find shelter soon. As they look to find shelter, Ash and Verity find a Charmander, which they quickly learn belongs to a ruthless trainer named Cross who left it out in the rain.

Cross refuses to take Charmander back, calling it weak, and Ash and Verity are forced to find it shelter. They come across a cave where Sorrel happens to be and help Charmander back to health. Sorrel reveals that Ho-Oh only gives the Rainbow Wing to the "rainbow hero" who is destined to fight it, as a shadow Pokémon named Marshadow watches. The next morning, Ash convinces Charmander to join them. The group follows the Rainbow Wing, which guides them towards the Raizen Mountain Range, to meet Ho-Oh. Charmander evolves into Charmeleon. Verity sees a Suicune at a nearby lake. Cross returns and challenges Ash's Charmeleon with his Incineroar. Charmeleon is savagely defeated, causing Ash much grief.

Upset over his loss, Ash openly admits that he could have won with Pikachu and later states that he wished he had gotten Bulbasaur or Squirtle. Alone in the woods, Marshadow puts Ash in a sleep-like state as the Rainbow Wing turns dark. Ash has a dream where no Pokémon exist and he attends regular school with Verity and Sorrel. Realizing something is missing, he remembers Pikachu and wakes up to his friends, and the Wing regains its color. They see a Raikou after Ash releases his Butterfree. The group realize they are getting close when the Wing begins to glow in the direction of Mount Tensei.

On the summit, the group makes it to a crystal-like structure called Rainbow Rock, but are interrupted by Cross who wants to fight Ho-Oh himself, having saw Ho-Oh too but didn't receive the Wing. Cross' Incineroar fights Ash's Charmeleon which quickly evolves into Charizard and defeats Incineroar. Cross, refusing to accept his loss, grabs the Wing and places it on the crystal, but due to his evil heart it turns dark, causing Marshadow, an agent of Ho-Oh's, to turn the local Pokémon evil and attack Ash and his friends. The Trainers fight back, but are overwhelmed by the severity of the situation. Ash finally withdraws a severely weakened Pikachu into its Poké Ball as the brainwashed Pokémon attack Ash, and he starts to fade as Marshadow notices the Wing has disintegrated. Pikachu's despair and sorrow was so powerful that its unleashes a massive and devastating Thunderbolt hitting Marshadow and its army, releasing them from Rainbow Wing's corruption. Pikachu continues to cry for its Trainer and best friend.

Ash finds himself in an alternative dimension, but is brought back. Ash takes the newly formed Rainbow Wing and places it on the crystal structure. Ho-Oh arrives, healing everyone and Ash challenges it with Pikachu to battle, but the outcome is never shown. Cross leaves on good terms and eventually Verity and Sorrel leave Ash to achieve their own dreams.

In the end credits, all of Ash's former travelling companions from Kanto to Kalos are shown. Verity is shown returning to her hometown. Sorrel and his Lucario, spot an Articuno which he wanted to study. Cross is seen travelling peacefully with his Pokémon. Ash and Pikachu travel on their own while being tailed by Team Rocket. The film ends as Ho-Oh drops a Rainbow Wing as it flies across the sky.

With no class today, Ash and Lana go Pokémon-fishing, but they may end up catching more than they bargained for since the lagoon they're fishing in may contain a water-type Totem Pokémon. If there is, then Lana is determined to battle it. Meanwhile, Kiawe takes the rest of the gang to visit his family's dairy farm, and Team Rocket doesn't seem to be having much luck with their own Pokémon-fishing.

As part of Lychee's practical lesson on Akala Island, the gang are sent on treasure hunts across the island mounted on Mooland, each of which reacts differently to its rider: Satoshi's Mooland is extremely friendly and enthusiastic, Suiren's Mooland does not seem to like her, and Lillie has trouble even getting close to her Mooland. In the first round, Satoshi finds three gemstones, Mao finds giant mushrooms, Kaki finds a large fossil, Suiren and Māmane find nothing and Lillie is still trying to approach her Mooland. In the second round, Suiren and Ashimari run into a hostile Pokémon which is fought off by her Mooland, an Alolan Isitsubute Satoshi mistakes for a fossil gets away when he tries to catch it, Mao finds a giant fruit, Kaki finds another fossil, Māmane uses technology to find a piece of meteorite, and Suiren finds a lump of metal that can be made into a Z-ring, making her the winner. At last, Lillie uses her experiences with Shiron and Pikachu to finally get close to her Mooland.

Lychee, the Akala Island Kahuna, and her Lugarugan appear at the school just in time to stop a fight between Kaki's Lizardon and a Kentauros. She completely wins over everybody's Pokémon including Nyabby. The class and Professor Kukui will be traveling to Akala Island for a special practical class under Lychee's supervision. On the way, they encounter various types of Sea Pokémon. After Satoshi and Pikachu join Lychee in an underwater swim, they find a Hoeruko trapped in a rock crevice by a vicious Hagigishiri. Now they have to help the Hoeruko and fend off the Hagigishiri at the same time.

As part of a class assignment, each of the students must take care of each other's Pokémon partner for the weekend. Pikachu gets to stay with Lillie at her mansion and Lillie is determined to try and overcome her fear of getting close to Pokémon, so she uses Satoshi's methods to gain Pikachu's trust. At Suiren's home, Bakugames is having trouble with her twin sisters, while Mao also has problems with Togedemaru while she works at her family restaurant. Māmane's experiments with Amamaiko don't work out well, but he finds that Amamaiko can be a great night-time comfort. At his family's dairy farm, Kaki assigns Ashimari to work with his younger sister Hoshi, but finds the water Pokémon to be a great problem-solver with the farm's Kentauros. Shiron keeps giving Satoshi the cold shoulder but finally warms up to him when Satoshi includes Shiron in his Pokémon's training sessions.

Ash and his classmates go on a camping trip in the forest. The trip does not start out well when Lana scares them all with a ghost story about a traveler who had all his energy drained from him while he was asleep. However, they have no idea that they are being spied on by a mysterious Pokémon. One by one, the gang except for Lillie is attacked, knocked out, and their energy drained from them. The culprit turns out to be a hungry Morelull. Ash figures out a way that the Morelull can get all the energy it needs from him, and later the gang finds out why the Morelull need so much energy.

PokéBase is a famous sport in the Alola Region and, after watching a match on television, Ash decides that they should have a match at school. The match gets really heated, but then Team Rocket appear and join in. Who will win the match?

While at the schoo, Ash learns of a powerful trainer who has come to Melemele Island. Ash eagerly finds this trainer and challenges him to a battle. The battle is strong with the trainer's Z Move coming into full force but soon after the battle starts, Lillie appears and confirms that this trainer is her brother, Gladion. Why is Gladion here?

Sophocles has overheard his parents seeking advice about moving and that means that Sophocles would have to leave the Pokémon School. Feeling down due to this, Ash & co. find out that he's moving and decide to throw a party for him. Will it cheer him up or is this an entirely big misunderstanding?

After seeing the power of Z-Moves while encountering Ash at the Pokémon School, Team Rocket decides to hunt for their own Z-Crystals so that they can keep level with Ash. In doing so, they encounter the Team Skull grunts who have been causing trouble on Melemele Island. In addition to that, while hunting for the stone, they discover the Totem Pokémon, Raticate. Will they find what they are looking for?

It's time for an open day at the Pokémon School and Ash gets chosen to hold a presentation to all the people attending. Trying to work out what his presentation should be, he learns that his mother is coming to visit from Kanto, which causes Ash to be even more nervous. Rotom then comes up with an idea to help Ash. Will the presentation go off without an issue?

Ash and co. are attending a concert being held on Melemele Island and see a performance by DJ Leo and his Dugtrio. Going backstage, Ash starts getting to know the Dugtrio, but the Dugtrio starts fighting with itself putting in the possibility of splitting up. Soon after that, Team Rocket appear with their eyes set on Dugtrio. Will Dugtrio be saved and able to reconcile its differences?

While training, Ash discovers a mysterious shovel moving aronud in the sand. Learning that it's a Pokémon called Sandygast, Ash learns of the dangers in touching the shovel. However, Sandygast's shovel flies off and angers tha Sandygast. Will Ash be able to help it?

While shopping, Ash & Pikachu find Litten and learn that it at Stoutland have found a new place to live. However, later Ash finds Litten all worried and panicked and decides to follow Litten to help out. What has got Litten so worried? Is Stoutland ok?

Hearing about Treasure Island from his classmates, Ash & Pikachu head to the island to explore. While there, it's the first time Ash & Pikachu have been out adventuring alone in a very long time and so they begin to strengthen their bond. However, before too long, a mysterious Pokémon appears overhead...

Ash has gone to visit Sophocles in order to learn the best way to try and defeat Tapu Koko in battle. Ash & Pikachu train with Sophocles in order to gain the upper hand, but soon afterwards Tapu Koko appears and challenges them. Will Ash be able to defeat the Guardian Diety of Melemele Island, or will he be defeated?

Mallow has come up with a new food item for the cafeteria, and Ash & co. all decide to ask Mallow to try it. However, the stew doesn't actually taste good and Mallow states that they need some Yellow Nectar in order to finish it, but the problem is that Yellow Nectar is hard to come by at the moment. Due to this, Ash & Mallow decide to go hunt for some Yellow Nectar, but it seems Team Rocket have a nefarious scheme at hand...

When he wakes up and heads to the Pokémon School, Ash soon finds that his Electirium Z that he earned has gone missing. Rotom, a huge fan of a crime show on Alolan TV, decides to search for the Electirium Z, wanting to act it out like the protagonist in that show. Will Rotom be able to find the Z-Crystal?

While Ash & Co. are playing on the beach, Popplio is making a bubble, but a gust of wind pushes Popplio and Rowlet into the bubble and they float away. When they land, they encounter the Litten that wanders around Melemele Island. It decides to take Popplio and Rowlet back to Ash, but Team Rocket soon arrive with plans of their own for Litten. Will they return to their trainers?

Rockruff has returned covered in scratches. Upon investigation, Ash & Kukui decide to record what Rockruff has been up to in order to find the situation. However, on looking at the footage, they see that Rockruff has been leaving the house every night to train so Ash decides to help it train up to become stronger. Will they succeed and find out why Rockruff has been training?

The egg that Lillie has been taking care of has finally hatched into a Vulpix. Everyone is overjoyed at this but Lillie's excitement soon turns to depression as she cannot pet the Vulpix she took care of as an egg due to her fear of Pokémon. Due to this, Ash and co. decide to encourage her and try and get her to touch and bond with the Vulpix, but soon a shadow has its eyes on Lillie. Will Lillie be able to bond with Vulpix?

Continuing his studies in Alola, Ash soon learns from Mallow about a famous Pancake Race. Intrigued, Ash and all his classmates enter in the special pancake race but while there, he meets the champion from last year, a trainer and her Alolan Raichu. A rivalry soon sparks between Pikachu and the Raichu and the race gets heated. Plus, with Team Rocket having their eyes on the prize, the race may not be as simple as they thought. Who is going to win?

Everyone has gone to the Melemele Sea for an extracurricular lesson, but Team Rocket have also come to the area in search of new Pokémon. However, while hunting for Pokémon by fishing, they soon discover a mysterious new Pokémon, Mareanie, and one of the Mareanie takes a liking to James. Will James get his first Pokémon in Alola?

As the Pokémon School isn't in session, Ash is practicing his Z-Moves. As he is doing so, he sees Kiawe fly by on a Charizard. Kiawe mentinos that he is helping take care of his family's farm to do a delivery. Ash is intrigued and decides to go visit Kiawe's farm and meet his family. However, trouble soon arises when Team Skull show up...

After completing the only Island Trial on Melemele Island, Ash decides to face off against the Island Kahuna Hala in the Grand Trial. Hala uses powerful Fighting-type Pokémon and moves causing Ash some trouble as he currently only has Pikachu and Rowlet. During battle, Hala unleashes the All-Out Pumelling Z-Move causing Ash to retaliate with a Z-Move of his own. Will he be able to win the battle?

As Rattata and Raticate cause trouble on the island, Ash decides to participate in the Island Trial Challenge. When meeting the Melemele Island Kahuna, Hala Ash says he is going to take on the trial, but Hala poses a question to him that Ash must answer before participating in it. Will Ash be able to answer the question and complete the trial?

Samson Oak has given the gang a task of looking after a special Pokémon Egg, but when it comes to night it was decided that the Egg should be kept at Lillie's house which makes Lillie uneasy as she doesn't like touching Pokémon. Ash goes with her and is shocked to see how big her house is. As the house is so big, it even has a garden where Pokémon play as well as a battlefield, so Ash challenges Lillie's butler to a battle. Who will win and what is in the egg?

Satoshi decides and fails to catch a stray Nyabby that continues to give him trouble.

Satoshi and Māmane are separated from their Pokémon during a visit to the local shopping mall.

Satoshi helps Suiren train her Ashimari to blow a water balloon large enough to enable undersea travel for people. During a school fishing trip, the class's Ride Pokémon are stolen by Rocket-Dan. However, Ashimari manages to blow a massive balloon to save all the Ride Pokémon from falling on the rocks.

After Satoshi fails to capture two wild Pokémon, he encounters a Mokuroh that lives in a Tsutsukera nest. After Satoshi feeds the starving Mokuroh, it returns the favor by helping him fend off Rocket-Dan away from its nest. Afterwards, Satoshi catches Mokuroh as his first Pokémon in Alola.

Professor Kukui gives Satoshi an intelligent Rotom Pokédex that is capable of human speech. Satoshi goes to find and catch his first Pokémon in Alola, but he instead encounters Rocket-Dan, who are aided by a wild Mimikkyu that despises Pikachu.

On Ash's first day at Pokémon school, Professor Kukui and the other students host a surprise welcome party for him. Soon after Tapu Koko approaches Ash in order to battle Pikachu. Tapu Koko teaches Ash how to use the Z-Ring. Ash and Pikachu manage to unleash the Z-Move, Gigavolt Havoc, but the Z-Crystal shatters after Pikachu's immense release of power. In order to regain the power of Z-Moves, Ash decides to go through the island trials.

Ash, his mother, and Pikachu arrive in the Alola region on vacation to deliver a Pokémon egg to Professor Oak's cousin, Samson Oak. While exploring for new Pokémon, Ash stumbles upon a Pokémon school that Samson runs as its principal. While helping to defend the school from a group of Team Skull grunts, Ash witnesses one of the students, Kiawe, perform a powerful Z-Move with his Pokémon to drive the grunts away. Impressed, Ash decides to enroll in the school to learn more about its native Pokémon. The night before Ash's mother returns home to the Kanto region, the guardian Pokémon, Tapu Koko, appears before Ash and gives him a Z-Ring that enables him to perform his own Z-Moves.