Can Zack save the planet from a barrage of butts from outer space? And not just any old rear ends, but an army of cunning, ruthless, zombie tushies! Twelve-year-old Zack would like nothing more than to wash his hands of the butt-fighting business, but when duty calls, Zack gathers his army of butt-fighters and sets off to stop the stinky invaders from Uranus.