Professor Oak and Tracey have a problem. The Pokémon in Professor Oak's garden are acting very agressive. Seeing the extremity in this case they call Ash for his Bulbasaur because Bulbasaur took care of and understood wild Pokémon in the past.

When Ash, Misty, and Brock run to investigate a mysterious chorus of bells that spontaneously ring out, they chance to meet their old friend Morty and a Pokémon researcher of his acquaintance. Morty and the researcher discover that the sacred Crystal bells, which are said to ring when a legendary Ho-oh returns, are missing. Since the bells were also used to heal the Bug Pokémon living in that area, these Pokémon lash out against their human neighbors, covering the town with their webs. Ash and friends decide to get to the heart of things and, in the forest, find Team Rocket restrained by webs and hanging from a tree. Ash, Misty, Brock, Morty, and the researcher begin to battle with the Bug Pokémon.