It is about three seventh graders that get stuck on an island and they try to escape but there is a laboratory on the island created by a mad scientist. The laboratory is used to create new animals like Jungle Walrus as mentioned in the episode. However, at the end of Junior Island the kids leave the island by a land bridge connected to the city, therefore, it was never an island, because they could've just walked, as one character suggested they do in the pilot. It gets stupider when Fern says in season 3, they get shipwrecked there again.