A boy named Shō remembers the week in summer he spent at his mother’s home with his maternal great aunt, Sadako, and the housemaid, Haru. When Shō arrives, he gets a glimpse of Arrietty, a Borrower girl, returning to her home through an underground air vent.

At night, Arrietty’s father, Pod, takes her on her first “borrowing” mission, to get sugar and tissue paper.