Yamper approaches with a Leaf Stone in his mouth, offering it to Goh. Considering what to do with the Stone, Goh notices his Exeggcute pass by and uses the Leaf Stone to evolve it into an Exeggutor. He scans Exeggutor with his Rotom Phone, learning that its three heads all think independently, but get along. Ash adds that Alolan Exeggutor are completely different to the Kantonian variant, measuring many times taller.
Soon, Professor Cerise informs the boys that they are heading to the Alola region and orders them to catch as many Pokémon on their visit. Ash and Goh take a plane and arrive on Melemele Island, where Professor Kukui is waiting outside the airport to pick them up. Ash formally introduces Goh to his close friend Professor Kukui, a teacher from the Pokémon School and part of his "Alola family". Kukui turns his attention to Goh's Raboot and the ever-nervous Sobble, adding that it the first time he has seen them in-person. Kukui then drives the boys to his home, where Professor Burnet, with her newborn baby Lei in her arms, welcomes them inside. Ash greets Lei, meeting him for the first time. Stepping inside, Ash's Alola team of Incineroar, Rowlet, Lycanroc, and Melmetal enthusiastically welcome their Trainer and Pikachu back with a group hug. Ash introduces them to Goh, and the Pokémon rush over in an equally excited manner. Before Ash and Goh can settle in, Burnet adds that Mallow and Ash's other friends have prepared a welcome party over at the School.
With that, Ash and Goh set off for the School at a running pace. Reaching the sand, they stop for a moment to admire the glistening blue sea around Melemele Island. Goh then spots something on the shore – a Pyukumuku. As Goh reads up on its Pokédex entry, Raboot steps on Pyukumuku and receives a punch in response. Goh tosses a Poké Ball and lands the catch. Next, the boys are chasing after a Grubbin through the forest. Ash informs Goh that Grubbin will escape underground if he doesn't pay attention. Ash and Pikachu decide to run ahead after the Grubbin escapes underground, only to lose track of Grubbin and Goh as well. Goh and Raboot, meanwhile, get side-tracked by something else burrowing, which soon reveals itself to be an Alolan Dugtrio. Unable to stop their running momentum, Goh and Raboot step off a cliff and fall into the water below. Goh is pulled ashore by Lana's fishing rod, while Sandy rescues Raboot. Lana greets Goh with an "Alola!", to which Goh remarks that he'd like to be put down. Lana rests Goh on her Ride Pokémon Lapras. As Goh introduces himself, Lana realizes that the boy’s name is exactly the same as Ash's friend. Ash and Pikachu, meanwhile, are spotted by a familiar friend, Rotom. Ash's Rotom Phone then scans Rotom with its Pokédex app, declaring that Rotom in its Pokédex Forme has no other functions outside of being a Pokédex. Rotom is insulted by the remark, rebutting that it has voice changing and recording capabilities as well. Rotom then returns its attention, adding that it has come to escort Ash and Pikachu to the School for the welcome party. Ash replies that they still need to find Goh, to which Rotom adds that Goh is already waiting at the School with the others.
At the School, Goh and his Pokémon are speechless and feeling nervous around all of Ash's friends. Sophocles is keen to dissect Goh's Rotom Phone to examine its technology, while Mallow and Lana's enthusiasm is proving overwhelming. Kiawe arrives at the School in a tense manner, introducing himself as Ash's Alolan rival. He wonders whether Goh is a strong battler and challenges him to a match to test his strengths, much to Goh's concern. A tense stare down between Kiawe and Goh ends when Rotom with Ash and Pikachu arrive.
Mallow declares that they can now get the party started. Everyone sits down to enjoy the delicious food and Pinap Berry-Honey drinks prepared by Mallow while they update Ash on the latest news. Sophocles reveals that he plans to return to the Mossdeep Space Center to research extraterrestrial Pokémon in his bid to become an astronaut. Lana then reveals that she just received a letter from Lillie. Goh wonders who Lillie is, to which Ash explains that she is one his former classmates and is currently on a journey to find her missing father. Lana reads the letter out aloud, which reveals that Lillie and her family are on board a train using Magearna's Soul-Heart to track down Mohn. Lillie promises to return to Alola once she has found her father, promising to write again in the meantime. Hearing how everyone is making progress on their dreams, Ash decides to challenge Kiawe to a battle. Kiawe, however, replies that he has already challenged Goh and is determined to evaluate his capacity as a rival. Goh is confused by the concept of being a rival, to which Kiawe shouts that the person closest to Ash must be strong to help him achieve his dreams. The others warn Kiawe that he is getting too fired up, Kiawe ignores their pleas and orders Goh to the battlefield. As Ash interjects, Goh immediately accepts the challenge after hearing Kiawe's sentiments.
On the battlefield, the match between Goh and Raboot versus Kiawe and Turtonator gets underway. Turtonator approaches with a Dragon Tail, but Raboot evades and strikes back a Double Kick, temporarily knocking Turtonator off-balance. Kiawe is impressed and decides to turn up the heat, activating the power of his Z-Ring. He warns Goh first, that he is about to face one of the most powerful moves in Alola, but Goh refuses to back down. As Kiawe remarks that he would expect anything less from one of Ash's rivals, Goh rebukes the comment, declaring that he is a friend and that everyone must strive to achieve their dreams on their own. Even so, Kiawe appreciates his courage before summoning his Z-Move, Inferno Overdrive. Goh orders Raboot use Ember to counter, however the effort is overwhelmed by the Inferno Overdrive. The attack steamrolls ahead, leaving Goh and Raboot to brace for impact.
As the explosive force of Inferno Overdrive hits, everyone on the sidelines is stunned to see Goh and Raboot emerge unscathed, with Kiawe's Marowak having intervened just in time. Ash remarks that this must have been Kiawe's plan from the beginning. Now smiling, Kiawe walks over to Goh and offers him a hand up. Goh instead grabs Kiawe's wrist and declares that while he is no rival, he can certainly look after Ash. Kiawe praises Goh’s stubbornness, having earned his trust. Raboot also receives a cheer from Kiawe’s Pokémon. Kiawe asks Goh what his dream is, and Goh confidently declares that he wants to catch every Pokémon, including the Mythical Pokémon Mew.
Hearing this, Ash and his former classmates take Goh to challenge an Alolan Exeggutor. Raboot uses Ember which strikes the gargantuan in the head and makes it unsteady on its feet. With that, Goh tosses a Ball and catches the Alolan Exeggutor. Ash and Goh return to the Cerise Laboratory, where Goh calls out his Alolan and Kantonian Exeggutor to admire their variant features. Goh tells Ash that they should visit Alola again sometime, and Ash promises that they will.