A bright young yeti finds something he thought didn't exist—a human. News of this “smallfoot” throws the simple yeti community into an uproar over what else might be out there in the big world beyond their snowy village.

14-year-old Arrietty and the rest of the Clock family live in peaceful anonymity as they make their own home from items "borrowed" from the house's human inhabitants. However, life changes for the Clocks when a human boy discovers Arrietty.