set in a magical swamp. Most of the mutant-like characters are "Groundlings", but look very different from each other. They can be described as any combination of animal, human, elf, and plant. One of the characters is a robot named Stacks. Generally, humans never appear in the series except as an alien presence represented by a boot or a voice. Most often, humans come to the marsh to dump trash and disrupt the ecosystem. The show was designed to be educational and so the story of each episode includes morals such as friendship, honesty, caring, and protection of the environment.