After hearing about Pokémon mysteriously falling ill on a hiking trail, Liko and Roy head there to investigate. They encounter Mollie, who has been working with her family at the local Pokémon Center and helping wild Pokémon in her spare time. Accompanied by Chansey and Maushold, she’s trying to heal a wild Furret that had been poisoned. Soon, more poisoned Pokémon appear, along with the apparent culprit—an angry Vileplume that Mollie says is usually friendly. Could Laquium be the cause of the disturbance?