Magearna Moves (Japanese: マギアナ、稼働くMagearna, Move) is the 595th chapter of the Pokémon Adventures manga, and the 47th and final chapter of the X & Y arc.
Several days later, Trevor and the students take a break and happen to come across Cassius at a cafè. Cassius explains that he's been the police station; Emma was arrested on claims of wreaking property damage, necessitating him to give a statement on her alibi. To continue the explanation, Cassius brings Trevor's group to the Lumiose Museum, where one of his gang members has taken up a new receptionist job. Cassius shows Trevor the damage was done, along with a surveillance photo of the Expansion Suit. Despite the Expansion Suit being under police custody, Cassius adds that the police accused Emma of hiding a separate suit to commit the crime; they have also been unable to interrogate Xerosic for more information due to rich ex-supporters of Team Flare preventing further investigation.
Studying the photo, Trevor spots the large ball he encountered also in the picture, which the receptionist confirms isn't a match for any of exhibits. Gurkinn's students identify the damage as being caused by Steel and Fairy-type moves. Remembering that Y lent him her Pokédex, Trevor tries to see if the Pokédex picked up anything on the large ball he encountered, and identifies the ball as Magearna, an artificial Pokémon created over half a millennia ago. Despite knowing that Magearna caused the damage, the group realizes they are no closer to solving the mystery, and decide to hold a stakeout after getting permission from the night watchman.
That night, following a long wait, Trevor and Cassius spot Magearna rolling up a stairway. The team move out to confront Magearna, who shifts into its activated form and begins defending itself against the students' Mega Evolved Pokémon, only briefly stopping at the sight of something and preparing to escape. Cassius orders his Gourgeist to use Trick-or-Treat on Magearna to make the students' attacks do more damage, but Trevor intervenes by having his Florges cover Magearna with Flower Shield. Before he can explain his actions, Trevor is pulled away by Magearna as it escapes. Confused, Cassius notices the night watchman taking one of the paintings, and is shocked to see that it's actually the Expansion Suit in disguise as the Suit breaks out of the museum.
Outside, a dazed Trevor wonders if Magearna pulled him away as thanks for protecting it. Pulling out his Holo Caster, Trevor shows Magearna footage of their battle and asked why it stopped attacking; Magearna points to a painting behind Cassius's Gourgeist as the reason. Trevor guesses that the painting must show someone significant to Magearna, but the pair is quickly accosted by the Expansion Suit, wielding a Barbaracle. While Barbaracle and Magearna trade attacks, Barbaracle forces Magearna to stand down by holding the painting the Expansion Suit stole, letting Barbaracle attack unimpeded. Trevor has Florges cover Barbaracle with Petal Blizzard so she can retrieve the painting, and Magearna uses Fleur Cannon to defeat Barbaracle and break the suit. To Trevor's surprise, the suit is completely empty. In an interrogation room, Xerosic reveals that this other Expansion Suit was a prototype he programmed to seek out Legendary Pokémon for capture, but he abandoned the project once Emma signed on to become Essentia. Believing that his work has developed sentience and autonomy, Xerosic begs for an audience with his lawyer to secure a new sponsor and bail him out of imprisonment.
Returning to the museum, Trevor is greeted by Cassius, Emma and the receptionist. Discussing the events, the receptionist explains that the painting might portray Magearna's creator, and thus the curator has granted Magearna special permission to visit the painting as often as it wants. Trevor prepares to take his leave, revealing that he's been in contact with another Trainer to take custody of the Delphox stolen and trained by Malva. Cassius recalls that Delphox refused to open up to Trevor or any of his friends, and wonders if the newcomer is an intimidating, threatening person. To his confusion, Trevor remarks that the Trainer is someone who any person or Pokémon would want to be friends with. Back at the lab, Trevor is greeted by Whitley, who has managed to convince Delphox to come with her after considerable effort.
Over a call, Trevor reports to X about recent events. X confirms that both he and Y are at Shalour City, where Korrina has been overseeing the reconstruction of the Tower of Mastery. Trevor suggests that Korrina called X and Y over because she felt lonely, and Y joins the call. Trevor confirms that both Gurkinn and Professor Sycamore have headed for Hoenn to continue their investigation into Mega Evolution, and the mention of Hoenn turns Y solemn. Y brings up an incident that happened before X moved to Vaniville, remarking that a lot of adults behaved much like how Team Flare did in response to the crisis. Thinking back, Trevor agrees, noting that not just Kalos, but the entire planet was engulfed with despair.
