Sho moves into his great aunt's house and soon discovers the presence of tiny people, the Borrowers, living there. A 14-year-old Borrower named Arrietty strives to prove herself by helping her father gather materials that her family needs from Sho's new home. However, Arrietty and Sho meet, breaking the rule that humans must not know about the Borrowers' existence. As Sho and Arrietty's relationship develops, human interference endangers the Borrowers' lives. Arrietty and Sho work together to try and protect the Borrowers' way of life.