The Borrowers live in the secret places of quiet old houses; behind the mantelpiece, inside the harpsichord, under the kitchen clock. They own nothing, borrow everything, and never forget their most important rule: you must never, ever be 'seen' by the human beans.

Arrietty is desperate to be an expert Borrower like her father, Pod. But it's dangerous work, and girls are forbidden to venture Upstairs. Arrietty is thrilled to be given a chance to prove herself - but disaster strikes on her very first outing: she is seen by The Boy! But to everyone's surprise, a wonderful, unlikely friendship is formed. But soon the Borrowers find themselves in terrible danger, and only The Boy can help.