Ep 27. Settling a Not-So-Old Score

Ash and his friends are on their journey to Sunyshore City in the Sinnoh region and decide to take a break at a Pokémon Center. While they are there, they come across an old friend, Gary Oak. Gary is now a researcher and has been studying Pokémon strength and abilities, especially those of Legendary Pokémon.

Gary invites Ash and his friends to join him on his search for the mythical Pokémon, Mew. They travel to a nearby island where Gary is convinced Mew is hiding. However, they soon discover that they are not the only ones looking for Mew. Team Rocket has also made their way to the island and is determined to capture Mew for themselves.

As Ash and his friends search the island, they come across a mysterious old man who seems to know more about Mew than anyone else. He reveals that he has a long-standing grudge against Gary's grandfather, Professor Oak, and blames him for the creation of Mewtwo, a powerful clone of Mew that nearly destroyed the world years ago.

The old man, whose name is revealed to be Dr. Yung, has been using his knowledge of Pokémon genetics to create his own Legendary Pokémon, with the intention of using them to defeat Mew and get revenge on Professor Oak. Ash and his friends soon find themselves caught in the middle of Dr. Yung's revenge plot, as they are attacked by his creations and must fight to protect Mew and the other Pokémon on the island.

In the end, Ash and Gary team up to defeat Dr. Yung and his creations, and Mew is able to safely return to its home. Gary reflects on the importance of treating Legendary Pokémon with respect and admiration, rather than using them for personal gain. The episode ends with Ash and his friends continuing their journey to Sunyshore City, excited for their next adventure.