The Green Guardian!

On their way to the Battle Pike, Ash and his friends decide to ride along the Cycling Road. However, it is closed and they must go through the forest. After hearing a noise, Pikachu wanders off and finds an wild injured Celebi under some thick vines. Ash and the others then meet a Pokémon Ranger named Solana who agrees to help them find Pikachu. When they finally find Pikachu and Celebi, the reunion is cut short as Team Rocket shows up to steal Celebi.