While exploring Izabe Island Ash & the others wind up above a Trapinch Labyrinth. They meet Elisa & Hal who are mapping the Labyrinth. Hal is also searching for an underground lake. Team Rocket attacks and try to steal Pikachu but thanks to Ludicolo & some Trapinch Team Rocket's Robot is destroyed but they end up in the Labyrinth with Pikachu! Ash & Elisa follow them and are soon followed by Hal. May, Max, & Brock also follow and they, Ash, & Elisa end up in the underground lake that Hal was talking about. Hal arrives and everybody sees the Trapinch evolve into Vibrava. Brock & Ludicolo once again battle Team Rocket with the help of the Vibrava. After Team Rocket is defeated Ash & the others ride the Vibrava up out of the Labyrinth. Elisa then tells them how to get to town and Ash & The others leave. (thetvdb.com)