For their second day in Malie City, Ash and his classmates plan to visit the Kantonian Gym, which Sophocles learns is actually a tourist attraction based on the Gyms in the Kanto region. As they look for their tour guide, Charlie Charma, Lana spots a fake wall from the corner of her eye and has Sandy attack it, but it turns out to be a decoy. An old man sitting across the street removes his disguise and reveals himself as Charlie, who claims his substitution technique fooled everyone and admits that entertaining his guests is part of being a tour guide. He then walks everyone over to the Kantonian Gym.
The tour group arrives at the unofficial Gym, a large pagoda decorated with hanging Darumaka and Darmanitan faces. Charlie claims the Kantonian Gym's architecture is based on the Kanto style, but Ash doubts this and Charlie is shocked to learn that Ash is actually from Pallet Town. Three other ninjas, Shirataki, Darley, and Farley, then land in front of the group, surrounding Ash and asking him what Kanto is really like. Charlie pushes them away and they bow to apologize for their rudeness. Ash wants to have a Pokémon battle with them, but Shirataki admits that their facility treats their guests to games instead. The ninjas explain that all entrants must complete the games on the first four floors before they can battle the Kantonian Gym Leader at the top. Lillie and her friends are excited by this prospect, so they all decide to try the Kantonian Gym out.
Farley takes the group to a large pond and fountain feature inside the Gym. He reveals that their first task is to cross the water. Lana decides to swim across, but Farley holds her back and explains that a participant must cross the water's surface without swimming. He presents the group with a box of tools and adds that they can use them and their Pokémon to cross the water. He demonstrates a pair of water shoes, gliding over the pond's surface with ease. Kiawe and Ash follow suit, but they quickly lose their balance and barely avoid sinking into the pond. Lillie gets an idea and has Snowy freeze over the water with Powder Snow, with Farley affirming that Pokémon can be used to assist the participants. With that, Lillie leads everyone across the frozen pond and Farley declares the first task to be complete. The staircase to the second floor slides down from the ceiling, allowing everyone to progress on to their next challenge.
Darley greets his participants and treats them to a banquet-style meal. Mallow looks at the food and spots something particularly odd, which Darley reveals is a Goldeen yōkan, a jelly desert common in Malie City. Everyone eats the food, and once they are finished, Darley announces that they have completed task. Lillie is surprised that all they had to do was eat, but Darley admits that the task was for participants to truly appreciate all that Malie City has to offer. The staircase to the next floor reveals itself and the group prepares to leave. However, Sophocles wants to eat more and Mallow is keen to learn the recipes of some of the dishes, so the rest of the group advance without them.
On the third floor, Shirataki reveals that the next task is to hit targets three times with shuriken. Ash picks up three shuriken and hits the target in one throw. Pikachu uses Iron Tail to knock three shuriken into the targets. Kiawe is successful as well, and his Marowak swings its bone like a club to hit the targets. Lana lands a total of six shuriken in the center of three different target boards with one throw. The anxious Lillie closes her eyes when she makes her throws, but she sends her shuriken flying in random directions, nearly hitting the others instead and forcing Lana to restrain her. As a result, Shirataki allows Kiawe, Lana, and Ash to advance to the next stage, while Lillie will continue practicing her throwing technique.
Charlie greets the trio on the fourth floor and reveals their next task, an obstacle course. Kiawe volunteers to go first and eventually clears the course completely. Ash passes the first few obstacles but finds himself in trouble with the balance beam section. He and Pikachu approach slowly, and as a swinging pendulum heads towards them, Ash calls out his Meltan to assist them. Meltan leaps onto the chain holding the large ball and eats through it within seconds. Ash ducks in time to avoid being hit, but the now-detached ball flies on and destroys the entire obstacle course, leaving Lana unable to pass. Ash and Kiawe subsequently advance to the final floor.
Ash and Kiawe arrive at a battlefield and announce their arrival. As billowing white smoke fills the air, Charlie guides the rest of the group to the spectators' seats to watch the unfolding battle. The Gym Leader Ryuki emerges from the haze and declares himself a star who is unwilling to change his red spiky style. Kiawe decides to take on Ryuki first, while Charlie takes his position as referee. Kiawe chooses Marowak, while Ryuki calls out his Zweilous, whose two heads instantly begin fighting. Ryuki screams into his microphone, and the pitch causes everyone to flinch and cover their ears. He goes into an air guitar performance as real music echoes through his stage setup. Zweilous's heads stop fighting each other and sway to the music. Kiawe tries to have Marowak attack, but it is too caught up in the music to listen. Ryuki has Zweilous use Dark Pulse, and with Marowak distracted, the attack easily hits its target. Marowak is sent backwards and lands on its head, getting knocked out. Charlie declares Marowak to be unable to battle, giving Ryuki the victory.
Ash then calls out Rowlet, who is asleep. As Ash tries wakes it up, Ryuki is concerned about Rowlet's slow pace. Ash, however, assures him that Rowlet puts in the effort when it needs to, and soon enough, Rowlet stretches out its wings to prepare for the upcoming match. Ryuki starts the music again, but Rowlet is unaffected and tries to use Tackle. Zweilous charges up Dragon Rush, but it subsides when Rowlet's Tackle hits. Ryuki has his Zweilous follow up with Bite. Rowlet avoids the first head, but gets caught by the second one. Zweilous then shakes its head to the music, shaking Rowlet. Angered by Rowlet's treatment, Meltan walks over to Ryuki and begins chewing through the metal in his outfit. The distraction halts the battle and Zweilous's heads resume their infighting. Ash rushes over to pick up Meltan and apologize to Ryuki, but he notices Meltan's drive and changes the match to a Double Battle. Mallow questions Ryuki's ability to challenge the rules so suddenly, and he responds by loudly proclaiming that he is the Leader and he gets to decide the rules. Ryuki calls for Ash to send his Meltan to battle, which he agrees to.
Ash's Rowlet and Meltan prepare to go up against Ryuki's Zweilous and Druddigon. Ash orders Meltan to strike Druddigon with a Headbutt, but the attack does nothing against Druddigon's rock-hard head. He then orders Rowlet to use Seed Bomb, but Meltan unleashes a Flash Cannon on its own. Ryuki has the two Dragon types sidestep to evade the attack, before ordering Zweilous and Druddigon to retaliate with Bite and Dragon Claw respectively. Rowlet flies out of the way, but Meltan finds itself intimidated by Druddigon's sheer size. Meltan builds up its Defense with Harden, but it takes several direct Dragon Claws. Ash orders Rowlet to distract Druddigon with a Peck attack, but Zweilous is waiting with its jaws wide open. Rowlet attempts to soar in several more times, but retreats to avoid being attacked. As Ash orders Rowlet to attack again, its Peck suddenly transforms into Brave Bird and strikes Ryuki's Pokémon. Rotom announces the new move, and Ash is thrilled by the development. Rowlet lands on the ground and Meltan rushes to hug its friend. Ash orders his Pokémon to attack together. The Brave Bird and Flash Cannon combo knocks Druddigon and Zweilous out, and Charlie declares Ash the winner of the match. Ryuki presents Ash with a Badge in recognition of the victory, featuring his face on it. Everyone is astonished by this, but understand that it's just a novelty item. Nevertheless, Ash and his supporting Pokémon perform a victory pose with their new Badge in hand.
As the evening rolls around, the group leaves Malie City's port and heads back towards Melemele Island by ferry. Kiawe swears to challenge the Kantonian Gym again and win. Ash is thrilled by his victory, while Pikachu notices Meltan eating something. Meltan turns around and reveals that it has already eaten half of Ash's Kantonian Gym Badge. Alarmed, Ash rushes in to save what's left of his souvenir.