On the way to Dawn's next Pokemon Contest in Lilypad Town, Ash and friends take a break in a forest. Dawn decides to have Mamoswine's contest debut in the contest, but when she starts to train with it, Mamoswine still shows some of its old disobedience. It isn't long before it gets angry and runs off into the forest after Pikachu and Piplup laughed at it, and Dawn has no choice, but to go after it. To make matters worse, a wild Tangrowth appears out of nowhere and taunts Mamoswine into battling it. After losing, Mamoswine hunts it down, determined to beat it. Meanwhile, a forest ranger named Verona warns Ash and Brock about the Tangrowth, and after finding out about Dawn, they go search for her.