On their way to the Battle Pike, Ash and friends decide to ride along Cycling Road. However it is closed and they must go through the forest below. After hearing a noise, Pikachu wanders away and finds an injured Celebi under some thick vines. Ash and the others then meet up with the Pokémon Ranger Solana who agrees to help them find Pikachu. When they finally find Pikachu and Celebi, the reunion is short-lived as Team Rocket attacks wanting Celebi for themselves! (thetvdb.com)