Ash, Misty, and Brock arrive in Gringy City, a now polluted city built along the shore with a skyline full of factories. When Pikachu falls sick, they head to the pokemon center to heal it. Nurse Joy says it is just a cold, but Ash is still worried. Soon the power goes out, and all the sick pokemon are now in extreme danger. Ash and the others decide to head to the Power Plant to find out what is wrong, and it turns out that a bunch of Grimer are clogging up the water system, and they have overrun the Power Plant. Not only that, Pikachu is still extremely sick, and all the plant's Magnemite are attracted to its energy.