In the second half of the Alola Pokémon League semifinals, Ash is battling Guzma, whose Golisopod had previously fled the match—resulting in the defeat of Guzma’s other partner, Scizor. With Golisopod back on the battlefield, Guzma begins reliving painful memories of past conflicts and his strained relationship with Professor Kukui. His frustration builds to a fever pitch, but it’s not enough to stop Ash and Pikachu from ruining his “undefeated” record and winning the match. After the battle, though, Plumeria and the Team Skull Grunts express admiration for his effort—giving him the strength to keep going despite his loss.
Next up are the finals: Ash versus Gladion!
Guzma remarks that his victory is still certain, brushing off Golisopod's poorly-timed Emergency Exit. He orders Golisopod to use Poison Jab, and it poisons Torracat. Golisopod follows up with Throat Chop, though Torracat evades it despite being afflicted by the poison. Torracat uses Fire Fang as it latches onto Golisopod's arm and engulfs it in flames. Golisopod shakes Torracat off and kicks it away, inflicting a lot of damage and defeating it. Nanu declares Torracat to be unable to battle, and Ash recalls it back to its Poké Ball to rest. Guzma is relieved, admitting under his breath that he was beginning to sweat.
Guzma is amused at Ash's next choice, Pikachu, and recalls that Golisopod easily defeated him last time. Ash remains confident, declaring that the battle isn't over yet. Spurred on by his cheering Team Skull Grunts, Guzma boasts that he will win and starts off with Poison Jab, though Pikachu slides between Golisopod's legs to evade it. Golisopod counters an oncoming Iron Tail with Liquidation and then slams him to the ground with Throat Chop. Hala and Professor Kukui realize that Guzma, despite his potential, has not changed at all. Plumeria privately hopes that Guzma wins for the sake of the many grunts who felt like outcasts before they joined Team Skull.
Pikachu is able to continue battling, though Guzma urges Ash to accept his loss and move on. Ash refuses to give up, which irks Guzma, who has Golisopod use Pin Missile. Pikachu protects himself with Electroweb before using Thunderbolt, which Golisopod blocks with its claws. However, Ash predicted this and has Pikachu strike Golisopod's legs with Iron Tail, knocking it over, before using Thunderbolt to electrocute it in midair. Guzma becomes increasingly furious and recalls the overwhelming humiliation he felt every time he lost to Kukui during their practice matches. Upon seeing this, Plumeria comes to the realization that Guzma's claim of being undefeated is fake. She sees he is very much like his Golisopod, as both hide behind their armor and run away to avoid being hurt. Just then, Ash charges up his Z-Ring and Pikachu launches Gigavolt Havoc, but Golisopod manages to withstand the Z-Move.
Seeing Golisopod's bold strength, Guzma is reinvigorated after reflecting on his past and left even more determined to test his limits. He orders Golisopod to use Pin Missile, which Pikachu evades with Quick Attack. Pikachu strikes back with Iron Tail, though Golisopod counters it using Liquidation. Pikachu fires Electroweb, though Golisopod shreds it with its sharp claws and uses Poison Jab. However, Pikachu evades it and uses Iron Tail, but that attack collides with Liquidation, which defeats Golisopod. Nanu declares Golisopod to be unable to battle and awards the victory to Ash, allowing him to advance to the finals. Ash looks at Guzma, who helps Golisopod up before recalling it to its Poké Ball. As Guzma prepares to leave the battlefield, Kukui stops him to say that he will be waiting for him in the next League. Guzma doesn't reply and continues walking away. Backstage, Guzma is greeted by Plumeria and his grunts backstage. He announces that the era of "undefeated" Guzma is over and orders everyone to go their separate ways. The grunts, however, are moved to tears, and Plumeria explains they were all inspired by his battle. She then assures Guzma that the grunts still want to follow him, as well as her own loyalty.
That evening, Ash's friends urge him to do his best in his finals match against Gladion. Meanwhile, at the docks, Gladion and his Pokémon stare at the sunset with anticipation. At the battlefield, Kukui wonders about the outcome of the finals match. Elsewhere, a swarm of Meltan walk along the seafloor and approach Manalo Stadium.