Julia Diggers has delayed the final stage of her students' training for long enough! Carla, Luan and Gar must enter the mystic Proving Grounds created by the founders of their martial art. The labyrinth of trials is designed to test the strength and will of students on the edge of mastery. But something is amiss within: A band of pint-sized, emerald-clad invaders have usurped the grounds' mystical forces and reformed them into an impenetrable baffle of deadly traps!