Residing quietly beneath the floorboards are little people who live undetected in a secret world to be discovered, where the smallest may stand tallest of all. Arrietty (voice of Bridgit Mendler), a tiny, but tenacious 14-year-old, lives with her parents (voices of Will Arnett and Amy Poehler) in the recesses of a suburban garden home, unbeknownst to the homeowner and her housekeeper (voice of Carol Burnett). Like all little people, Arrietty (AIR-ee-ett-ee) remains hidden from view, except during occasional covert ventures beyond the floorboards to ''borrow'' scrap supplies like sugar cubes from her human hosts. But when 12-year-old Shawn (voice of David Henrie), a human boy who comes to stay in the home, discovers his mysterious housemate one evening, a secret friendship blossoms. If discovered, their relationship could drive Arrietty's family from the home and straight into danger.