As Serena trains with her mother to become a Rhyhorn racer—with little success or enthusiasm—Ash, Clemont, and Bonnie are in Lumiose City, racing to Professor Sycamore’s Pokémon Lab to get help for Froakie, who took a lot of damage during the battle with Team Rocket. The professor welcomes them and puts Froakie under the care of his assistant, Sophie, where he’s sure it will recover in no time. He explains to Ash and the others that Froakie is an unusual case—though it’s a Pokémon meant for new Trainers, it doesn’t always listen to them, and it’s been returned to the lab more than once. This shocks Ash, who admires the fearless Froakie for the way it saved Pikachu.
Sycamore also talks about his research on Pokémon Evolution, including a newly discovered phenomenon known as Mega Evolution, where even fully evolved Pokémon (like the friendly Garchomp that lives at the lab) can evolve again—and then return to their previous form. The science-minded Clemont is very intrigued…and so are Jessie, James, and Meowth, eavesdropping as usual. They decide to catch Garchomp and figure out how to make it Mega Evolve—but when they spring out of hiding and clamp a collar around Garchomp’s neck, it goes into a rampage, blasting them off immediately and crashing through the city until it ends up at the very top of Prism Tower.
Ash goes after it, determined to get the collar off. With the help of one of Clemont’s brilliant inventions, he gets into the tower through a back entrance and starts climbing, with Pikachu and Froakie on his shoulders. There’s a huge crowd at the base of the tower watching Ash’s courageous rescue—and a news crew broadcasting the whole thing on TV, where Serena and her mother are watching.
Struggling with its collar, Garchomp nearly steps off the edge of the tower, but Froakie acts fast and glues its feet to the building with some sticky Frubbles so it won’t fall. With Garchomp secured in place, Ash finally manages to get close to it, and a handy Iron Tail from Pikachu slices through the collar. The weary Garchomp is finally free!
Professor Sycamore thanks Ash for his bravery and gives him a new Pokédex for his journey. And it seems Ash will have a new friend to travel with, because as he turns to leave, Froakie blocks the way and presents Ash with its own Poké Ball. So, with Froakie on hand as his first Pokémon from the new region, Ash sets off on his journey in Kalos!