Mega Evolution - Roy (Japanese: ロイ ――修行Roy—Training) is the 112th episode of Pokémon Horizons: The Series, and the 1,344th episode of the Pokémon animated series. It first aired in Japan on October 10, 2025, in the United Kingdom on February 27, 2026, and in Australia on April 2, 2026.
Spoiler warning: this article may contain major plot or ending details.
On the Brave Olivine, Liko and Dot are watching Roy and Ult engage in a battle. Ult Mega Evolves his Sableye into Mega Sableye and Roy follows up by Mega Evolving Lucario into Mega Lucario. The two Mega-Evolved Pokémon exchange blows, with the winner of the battle being unknown. Liko and Dot mention how the two boys had been training in Kalos together before wondering how Roy met Lucario. Roy reveals he went on a journey to Lumiose City with Crocalor, Kilowattrel, and Captain Pikachu.
Upon arriving in the city, Roy is instantly amazed by the view of the place and eager to grow stronger as a Trainer. However, he gets lost while trying to get to somewhere. Cap tries to help the young Trainer, but he is forced to get away from some people who accidentally triggered his "allergy". Roy follows him and ends up at Lumiose Gym. The sound of a battle grabs the group's attention and being curious about it, Roy accidentally runs into Ult. The two get into an argument despite Roy apologizing before getting distracted by the battle again. When they take a closer look, they see a battle between a Gardevoir and Slowbro. Gardevoir uses Moonblast on Slowbro, but the Hermit Crab Pokémon uses Amnesia to power up and negate it. Slowbro then retaliates with Hydro Pump that is evaded. The Trainers of the two battling Pokémon Mega Evolve their Pokémon into Mega Gardevoir and Mega Slowbro, respectively, and Roy becomes excited upon seeing Mega Evolution up close. Ult ridicules Roy for being excited at Mega Evolution, retorting how Sableye would be able to do it if he was interested, prompting Roy to return to the battle while being unsure what to make of Ult. The battle ends with Mega Gardevoir dealing the finishing blow on Mega Slowbro and a strange person on the side promotes Mega Evolution to the crowd. Roy and Ult, being the only ones interested, immediately come up to him to ask about Mega Evolution and the guy introduces himself as Master Mayonnaise.
Master Mayonnaise brings the two boys to a café to discuss about Mega Evolution further. He begins by explaining what is Mega Evolution to Roy and Ult before revealing the conditions to Mega Evolve. The first condition is having a Key Stone that resonates with a Pokémon's Mega Stone and the second is a strong bond between a Trainer and their Pokémon. Roy and Ult become eager at the idea of their respective partners Mega Evolving, but Master Mayonnaise points out no one has seen a Mega Evolved Crocalor before. Roy doesn't become disheartened by that as he focuses on being the first to Mega Evolve Crocalor. Master Mayonnaise gives the two boys Mega Rings to begin their training in mastering Mega Evolution, telling them to find Mega Stones next since they're usually hard to find. Ult reveals Sableye found its Sablenite while looking for shiny stuff. Crocalor brings over a random rock to not fall behind before the two boys head off.
Roy and Ult look for the Lost Mayo Maze based on a recommendation from Master Mayonnaise, who tells them to challenge the strongest Pokémon in there, the Yellow Flash. Roy realizes Ult would be able to bring them to Lost Mayo Maze since he knows the layout of Lumiose City, but the latter refuses, telling the former to find the way himself. After some struggle, Roy successfully arrives at Lost Mayo Maze, with Ult showing up shortly after. The two enter the palace cautiously and separate to find the Yellow Flash first. However, the layout of the place gives them a hard time finding the Yellow Flash until Crocalor and Sableye bump into each other. Roy and Ult run after their Pokémon and see a door on the other side of a long hallway. Believing the Yellow Flash is behind the door, Ult runs ahead first. Unfortunately, he falls into a trap before Sableye could warn him about it, though Ult is able to get out with Kilowattrel's help. As they are stumped on their next move, Crocalor finds a strange spot on the wall. Pushing it, he discovers a hidden passage way with a set of stairs that eventually leads the group to the Yellow Flash, which is revealed to be a Shiny Lucario, who challenges them to a battle. They begin by getting Sableye and Crocalor to use Power Gem and Flamethrower respectively, but the Yellow Flash dodges it all seamlessly. Due to its high speed, the Yellow Flash manages to attack Sableye and Crocalor before they could dodge. Roy and Ult get their Pokémon to attack again, but the Yellow Flash knocks them out before they could even attack, leaving it the winner as Roy and Ult are shocked by the strength of the Yellow Flash.
The title text for this episode is shown directly over the background, without a separate title card segment. As such, the title is not read aloud. Since there is no opening theme, the series logo (with the arc subtitle) is shown directly over a shot of Lumiose City.
This episode does not contain any eyecatches, instead having the series logo on a corner of the screen before and after the commercial break.
This is the last episode to air in Japan before the release of Pokémon Legends: Z-A.
The Taiwanese Mandarin and Hong Kong Cantonese dubs of this episode were released on the Traditional Chinese Pokémon YouTube channel at 6:30 PM (UTC+8), at the same time the Japanese version was released on the Japanese YouTube channel after its television airing. In the regular episode order, the Taiwanese Mandarin dub was midway through the second season, while the Hong Kong Cantonese dub was between the first and second seasons.
The Korean dub of this episode aired on October 14, 2025 (four days after the Japanese airing), before the Mega Voltage arc.
During the ending animation, a blurry photo of Looker (alongside Croagunk) can be seen at the Looker Bureau where Roy and Ult were eating and where Emma was serving them food.
This is the only time Ult's Sableye was shown holding its Sablenite as when Ult took it out of his pocket to show it to Master Mayonnaise, Sableye reached out for it and held onto it for the remainder of the scene. Similar to Dawn's Piplup and his Everstone, Sableye has not been shown holding the Sablenite ever since and the Mega Stone would just magically appear before it when Sableye Mega Evolves.
In the English, Taiwanese Mandarin, Korean, and other dubs, the on-screen "Mayo-Maze Palace" text is removed.
In the Hong Kong Cantonese dub, the on-screen "Mayo-Maze Palace" text is replaced with the local script.
In the Korean dub, clips of Roy and Ult Mega Evolving Lucario and Sableye are used at the very beginning of the episode (before the cold open) for an 8-second logo segment.
In the English and other dubs, the ending theme uses clips from all three variants of the Japanese version. This same version animation is used for the other episodes of the arc, instead of different ones for each episode like in the original
