Ash and Goh's training with Riolu and Farfetch'd, respectively, is cut off by Professor Cerise appearing and handing them tickets to a World Coronation Series Master Class battle in Galar, with Leon himself taking part in the match. Excited to see Leon battle, the two immediately head off to Galar.
Later, at Wyndon, Ash and Goh rush towards the Wyndon Stadium, almost being late for the battle due to Ash having seconds for his lunch and Goh eating extra dessert. Ash is momentarily distracted by a statue in the entrance hall, but quickly follows Goh to the stands, where they let Riolu and Farfetch'd out of their Poké Balls to watch the match. The announcer gives a brief insight into the World Coronation Series: the tournament has over 10,000 participants, but only the Top 8 can stand in the Master Class and be referred to as the Masters Eight. The first Trainer to enter the battlefield is Raihan, a Galarian Dragon-type Gym Leader, who's currently ranked seventh in the tournament, having climbed his way up into the Master Class as soon as he joined the event. His opponent is none other than Leon, the undefeated Champion of Galar and the current Monarch. As the referee explains that the battle will be one-on-one, Raihan tells Leon that he joined the event to end his winning streak. Leon's confidence remains unfaltered as the two Trainers take their places and send out their Pokémon. Leon sends out his ace Charizard, while Raihan chooses Duraludon, a Pokémon that Ash nor Goh has seen before.
At the referee's signal, the match begins, with Duraludon making the opening move with Metal Claw. The attack connects, with Duraludon moving surprisingly fast despite its metal-covered body. Charizard responds by using its own claw move, Dragon Claw. Ash and Goh noticed that Leon has changed up his Charizard's moves since last time. Duraludon uses Iron Defense, blocking the move with its impressive defensive capablities. Duraludon attacks with another Metal Claw, but Charizard uses Dig before the attack can connect, dealing notable damage on Duraludon while avoiding its attack. Charizard continues the assault with Brick Break, but Duraludon counterattacks with Stone Edge. Raihan's attack makes contact, dealing super effective damage on Charizard. Raihan decides to finish the match and calls for the ultimate Steel-type attack; Steel Beam. As the move charges, Ash and Goh check its info on Goh's Rotom Phone, learning that Steel Beam sacrifices the user's stamina for immense destructive force. The attack fires and overpowers Charizard's Flamethrower, slamming it down to the ground. However, despite all the damage it has taken, Charizard still stands up.
Raihan responds to Charizard's resilience by recalling Duraludon and Gigantamaxing it, with Leon also Gigantamaxing Charizard in response. Duraludon uses Max Rockfall, which Charizard counters with Max Knuckle, both countering the attack and dealing damage of Duraludon. Raihan next issues a Max Steelspike, but before the attack can make contact, Charizard uses its signature G-Max Move, G-Max Wildfire, slicing through the spikes before hitting Duraludon. The move's secondary effect damage is too much for the weakened Duraludon to handle, at it falls down, defeated, meaning that Leon's winning streak still remains unbroken. Raihan thinks to himself that he needs to polish his skills at at his Gym before rechallenging Leon. As the two shake hands, Raihan tells Leon that he's still going to break his winning streak someday. Ash suddenly cuts in on this, yelling down from the stand that he intends to be the one to defeat Leon, much to Goh's embarrassment. Leon recognizes Ash and waves at him, but then starts waving in another direction, with the announcer acknowledging Chairman Rose's presence.
At the entrance hall, Ash and Goh observe the statue from before. As they wonder if it depicts Leon, a young woman nearby catches their attention. She tells the two that the statue actually depicts a legendary hero from Galar's past, and starts detailing the legend to them. A long time ago, a great black storm covered the region, and giant Pokémon ran rampant, but the chaos was eventually stopped by a single young hero wielding a sword and a shield. The young woman admits that many details of the legend remain unclear, like who the young hero was, where did the sword and shield go, and what relation the event has to Dynamax. She remarks that she's doing this research as homework for her grandmother, who's a Pokémon Professor, being her assistant. Ash and Goh introduce themselves, and the young woman introduces herself as Sonia.
Later, while Ash and Goh are thinking about the legend, a Trainer carrying a fainted Chewtle asks them for directions for the local Pokémon Center, telling them that he was defeated by a strong Pokémon a nerby bridge. The two decide to investigate and go to the bridge, where they encounter a Farfetch'd carrying a huge leek. Goh's Rotom Phone informs them that this is Farfetch'd's regional form. Goh throws a Poké Ball at it to catch it, but it simply slaps the Ball away. As such, Goh sends out his Kantonian Farfetch'd to battle it and issues a Night Slash. The Galarian Farfetch'd responds with the same move and easily defeats Goh's Farfetch'd.
Farfetch'd seems eager for more battling, but before Ash can send in Pikachu, Riolu emerges from its Poké Ball on its own to battle. As such, Ash decides to put Riolu's earlier training to the test. Riolu opens with Vacuum Wave, but Farfetch'd blocks it with its leek, before winding up for another Night Slash. While it's winding up, Riolu hits it with a Force Palm, but despite the hit, Farfetch'd charges in. Ash counters with another move Riolu picked up during training, Double Team, causing the Night Slash to miss its mark. Riolu then bombards Farfetch'd with a flurry of Vacuum Waves, but after a moment, it sweeps them all aside with yet another Night Slash. Riolu uses Double Team again, but Farfetch'd uses Brutal Swing, dispelling all the copies and hitting the real Riolu. Despite the powerful hit, Ash knows that Riolu still has strength left, and issues a Reversal. The move hits Farfetch'd hard, but it's still not down. To Goh and Riolu's bafflement, Ash suddenly starts encouraging Farfetch'd to go on as well. Farfetch'd stands up, ready to go on, but as Ash and Riolu prepare to continue, they see Farfetch'd's leek slumping down, showing that it has fainted while still standing.
Ash and Goh bring all of their exhausted Pokémon and the Galarian Farfetch'd to the Pokémon Center, where Nurse Joy and her two Indeedee treat them all back to full health. Afterwards, outside the Pokémon Center, the Galarian Farfetch'd displays its eagerness to still battle more. Seeing this, Ash asks it if it wants to join his team, so that it could get stronger with his other Pokémon. After a moment of consideration, Farfetch'd accepts the offer, and Ash throws a Poké Ball at it, making his first capture in the Galar region. As soon as he lets Farfetch'd out of its Poké Ball, it immediately starts training with Riolu. As Goh joins in, a camouflaged Sobble appears behind him, momentarily observing the action, before being scared away by the loud noises of the training.