Meet Pedro. He's tiny, but he's looking for a BIG adventure. When his first try at an adventure goes a bit wrong, Pedro is rescued by the ADVENTUREMICE! They are a brave, determined team who keep all the Mouse Islands safe from harm. Pedro's dream is to show he's heroic enough to join their ranks. And soon he gets the chance to prove himself, when a big, scary otter starts causing trouble in the waters nearby . . .