Celebi comes to the rescue of Pokémon under threat from a forest fire, but the effort leaves it exhausted and it creates a giant tangle of vines to protect itself. A day later, Ash and his friends reach the Cycling Road, which is temporarily closed. Pikachu suddenly runs into the forest, and Ash gives chase only to be stopped by Solana, a Pokémon Ranger. She lets them through in order to find Pikachu, but giant vines have sprouted everywhere—the real reason why the Cycling Road is closed.
Solana recruits some Pokémon to clear a path through the vines, freeing a trapped Team Rocket along the way. The group then catches up with Pikachu, who ran off to help Celebi. Our heroes all watch over Celebi until it recovers and once it's back in good health, the vines disappear.
Team Rocket returns and captures Celebi using their latest robot, so Solana and her Plusle spring to the rescue. Celebi is freed, and Team Rocket is sent packing by Pikachu and Marshtomp. But the wrecked robot nearly starts another fire, and Celebi quickly intervenes to save the forest once again. With its job done, it returns home, wherever—or whenever—that may be. And now that the vines are gone, our heroes can take the Cycling Road to Fuchsia City after all!