On their way to the Grand Festival, the gang stops at an island filled with berries. May decides to make PokéBlocks, but no one except a wild Munchlax likes it. When Munchlax is blamed of eating everyone's PokéBlocks, May decides to prove them wrong and capture Munchlax.
This episode was the first to feature a Generation IV Pokémon, which was Munchlax. Munchlax didn't make an appearance in the seventh Pokémon movie, but this was the first episode to feature this Pokémon. In this episode, May's Purple Surprise, a PokéBlock which is enjoyed by Jessie and Munchlax only, is introduced in this episode, as well as the intense spiciness of the Tomato Berry.