While our heroes are having lunch on the path to Nimbasa City, a Roggenrola comes crashing down on them, ruining their feast! Ash decides he wants to catch it, so he makes a couple of attempts using Tepig and Oshawott. The Pokémon are unsuccessful, and they end up needing to visit a Pokémon Center. All this time, the Roggenrola seems to be urgently trying to tell them something. However, in a hurry, our heroes ignore the Roggenrola and leave it behind.
It is at the Pokémon Center that we discover its water source, located in a cave, has been mysteriously cut off. Accompanying a representative from the water company named Garrison, our heroes go to the cave to investigate. We discover that it’s Team Rocket who is to blame for blocking the water supply! They’ve also been catching the Roggenrola that live in the cave in order to implement a new weapon Doctor Zager has invented, which concentrates the power of the Roggenrola’s energy core.
Angrily, our Ash and his friends fiercely battle Jessie, James, and Meowth, and soon the Roggenrola are freed. Garrison arranges to have the water supply restored to the Pokémon Center. Ash also discovers the Roggenrola they first encountered wants to go with him. A battle ensues between Roggenrola and Tepig, and this time Tepig prevails. Roggenrola joins the group as Ash’s newest Pokémon friend!