Pokémon — Episode 28: The Thief That Keeps on Thieving!

You are watching the episode The Thief That Keeps on Thieving! When on their way to Pastoria City, Ash and friends meet a trainer named Tyler that wants to catch a Yanma. But Team Rocket ends up catching it after he weakened it. After Jessie captures the Yanma and sends it to Giovanni, who rejects it, she decides to train it herself and it quickly evolves into Yanmega.