The Cavity Creeps are a race of evil, tooth-hating creatures at war with the Crest Team, defenders of the city of Toothopolis. The city is surrounded by a wall of teeth that must be constantly defended against decay. The Creeps bring a variety of weapons, both low-tech (picks, hammers, catapults) and high-tech (jet fighters, rocket packs), as well as clandestine (a Trojan-horse style giant birthday cake) to mount their assaults.