Pokemon Season 12 Episode 578 - Leading A Stray! Episode Title:Leading a Stray!.Episode Description:As Ash, Dawn and Brock head to Chocovine Town for Dawn's next Pokémon Contest, they find Wailord blocking the water so they can’t take the boat. So they stop and have some lunch. Suddenly, a Luxio appears and begins to steal food from Ash and friends! Ash chases it into the sewer to find it is giving the food to a Wailmer who is trapped and can't get back to the ocean. Meanwhile, Dawn and Brock are unable to get to Ash because Team Rocket damaged the manhole. Then Ash and the Pokémon in the manhole think of a plan to get the Wailmer back to the ocean. The plan was a success. Dawn and Brock find them after Mamoswine broke the manhole. Then a Swampert blocked the path so they couldn't leave. Ash uses Grotle's Razor Leaf to defeat Swampert. Wailmer evolves into Wailord and happily makes it back to the ocean with its friends. Now Ash and friends once again head to Chocovine Town.