The beautiful town of Greenfield is under threat when a crystal catastrophe is unleashed, and it's up to Ash, Pikachu and their friends to figure out how to undo the damage. But when the powerful legendary Pokemon Entei kidnaps Ash's Mum, Ash must rescue her. But what lies ahead is not what it seems; the real secret power behind all the strange occurrences is a young girl whose nightmares are becoming reality by one of the most unstoppable Pokemon ever, the Unown.