In the Monster Soul world, a war was waged between humans and monsters, with the monsters falling on the losing end of a treaty. The peace between the monsters and humans is tenuous and monsters are frequently persecuted by humans. As a result, monsters tend to stay away from humans and keep a low profile. One group of monsters, known as the Black Airs, lives boldly with a purpose: to have fun and take care of each other. They get in to all kinds of trouble with reckless abandon, but as long as they stick together, they'll be all right ... probably.