When big trouble threatens the big city, it's up to Ash, Pikachu, and their friends to stop it! A vast Pokémon habitat amid the hustle and bustle of the big city seems like the perfect new home for a group of five Genesect. The arrival of these Mythical Pokémon quickly becomes a problem, though: their nest threatens the city's power supply, and they keep attacking anyone who approaches it. On top of that, they've attracted the attention of the Legendary Pokémon Mewtwo, who sympathizes with them because its own origins also involve human tampering. Their leader, a red Genesect, doesn't trust Mewtwo, and their confrontation quickly rages out of control! Can Ash and friends stop these two powerful Pokémon before they destroy the city?