After hearing the news that the Opelucid Gym is closed, Ash and co. decide to head to Tachiwaki city for Ash’s final Gym Challenge. On the way they encounter Iris’ rival Georgia, who’s looking for moss that powers up Pokémon created from the thorns of a Ferroseed. However, some of the moss grows out of control and covers the whole building, with Iris trapped on the roof with Axew, Ash’s Oshawott and Georgia’s Vanilluxe. How will she get out of this one?