Not knowing what else to do when his parents are mysteriously murdered one night, Sullivan retreats into the forest. Lost and scared, Sullivan stumbles upon a tree fort complex from which five boys wage war against an army of gruesome mud monsters that has invaded the forest. Sullivan soon realizes that in order to figure out what happened to his parents, he must unite with the boys, join in their fight against the mud monsters, and unravel a secret known only by a mysterious man who lives alone in the forest and calls himself the Hermit.