While our heroes are in Lumiose City, Serena suggests they visit Professor Sycamore before they continue their journey, and she’s even made a batch of delicious macarons for the occasion. At the professor’s lab, they settle in with a nice cup of tea, only to discover the macarons are missing! They find the basket of treats in a corner, guarded by a very hungry Chespin who isn’t interested in sharing.
Meanwhile, Team Rocket has been researching Professor Sycamore’s studies on Mega Evolution, and the villains decide that stealing his data would be a big boost to their schemes. They break into the lab grounds, grab the professor, and throw him in the back of their truck. He’s not alone, however—Bonnie and Serena manage to sneak aboard before they drive away. The girls get locked inside by accident, but Serena manages to leave a trail of broken macarons—which Chespin quickly sniffs out, leading Clemont and Ash to the villains’ hideout!
In the meantime, James has plugged Professor Sycamore’s data into a mechanical Mega-Mega Meowth, which attacks our heroes! Chespin lets Clemont know it wants to battle, but neither Chespin nor Pikachu can make a dent in the mighty machine. But then, the Mega Blaziken that rescued Ash when he fell from Prism Tower reappears, along with its Trainer, a mysterious man in a Blaziken mask. Mega Blaziken’s incredibly powerful Flamethrower leaves Mega-Mega Meowth charbroiled, along with the actual Meowth who’s been controlling it, and Team Rocket is sent blasting off again. As our heroes head back to the lab with the professor, Mega Blaziken’s Trainer is watching over them—now without his mask. It’s Meyer, Clemont and Bonnie’s dad!
At the lab, Ash, Serena, Clemont, and Bonnie are saying their farewells when Bonnie notices Chespin watching them. Clemont thanks the Pokémon for its help against Team Rocket and says they’ll meet again soon, but it seems clear that Chespin wants to come along! And so, with Clemont’s friend Chespin now part of the group, the journey to Cyllage City continues!