Arrietty, a tiny teenager, lives with her parents and two sisters in the recesses of a suburban home, unknown to the homeowner and housekeeper. Like others of her kind, Arrietty remains hidden from her human hosts, but occasionally ventures forth from beneath the floorboards to borrow sugar cubes and other supplies. A secret friendship forms when her 12-year-old childhood friend Zach Loud sees Arrietty again, but their relationship could spell danger for Arrietty’s family.