A Trainer and Child Reunion! - S11.E47

As Ash and the gang are heading back to Hearthome City, they encounter Aaron, a member of the Elite Four. They see that he's training his bug Pokémon, but also himself. He explains to the gang that he's trying to look for a Wurmple he released as a child as he felt it could become stronger on its own, but he wants him back. The gang offers to help Aaron look for his released Wurmple. They find Aaron's Wurmple, but since then it has evolved into Beautifly. The two become a team again. In the end, Aaron happily says thank you and a farewell, and Ash and his friends head on to Hearthome City.