Ep 16. Explorers of the Hero's Ruin!

In Pokemon season 15 episode 16, titled "Explorers of the Hero's Ruin!", Ash and his friends venture into the ruins of an ancient city in search of a hidden treasure known as the Hero's Sword. Along the way, they encounter a group of archaeologists who are also searching for the sword and ask for Ash's help in navigating the treacherous paths of the ruins.

As they make their way deeper into the ruins, Ash and his friends uncover clues that lead them closer to the treasure. However, they soon realize that they are not alone in their search for the Hero's Sword, as a group of thieves known as the Team Rocket Trio are hot on their heels.

With the help of their Pokemon, Ash and his friends must outsmart the thieves and navigate the dangerous ruins to uncover the secrets of the Hero's Sword. Along the way, they encounter powerful Pokemon and learn about the history of the ancient city and its legendary hero.

As the adventure comes to a close, Ash and his friends discover that the true value of the Hero's Sword was not in its treasure, but in the lessons they learned and the bonds they formed while on their quest. They leave the ruins with a newfound appreciation for the power of teamwork and the importance of never giving up on your dreams.