Ep 48. The Legend of X, Y, and Z!

Ash, Serena, Clemont, and Bonnie arrive in the Kalos region, where they hear about a legendary Pokémon known as Zygarde. They soon meet a researcher named Dexio, who tells them the story of Xerneas, Yveltal, and the mysterious Z, a Pokémon that has yet to be discovered. As they learn more about the legend, they also encounter a mysterious woman named Emma, who seems to be searching for something.

As they explore the region, the group comes across an ancient ruin where they find a strange symbol that resembles the letter Z. Dexio tells them that this symbol is associated with the legendary Pokémon Z, and that it may hold the key to unlocking the mystery of its existence.

The group's journey becomes more complicated when they are confronted by Team Flare, a nefarious organization that seeks to use the power of legendary Pokémon for their own ends. Team Flare has already captured the legendary Pokémon Zygarde, and they will stop at nothing to get their hands on Xerneas and Yveltal as well.

In the midst of all this chaos, Ash and his friends continue to search for clues about the legendary Pokémon Z. They soon discover that Emma is actually a member of a secret organization known as the Lumiose Lab, which is dedicated to studying the legendary Pokémon of Kalos.

As the group gets closer to uncovering the mystery of Z, they find themselves in a race against time to stop Team Flare from unleashing the ultimate power of the legendary Pokémon. Along the way, they will encounter new friends and allies, and face off against some of the most powerful trainers in the region.

In the end, the group will discover the truth about the legend of X, Y, and Z, and uncover the secrets of the Kalos region's most powerful legendary Pokémon. With their newfound knowledge, they will be able to protect the region from those who seek to harness the power of these ancient creatures for their own gain.