When young Sara (Liesel Matthews) is sent to a boarding school by her well-meaning World War I-bound father (Liam Cunningham), the imaginative girl makes the best of things by entertaining her friends with fanciful tales. After running afoul of the strict headmistress, Miss Minchin (Eleanor Bron), Sara receives some heartbreaking news, and is forced to work in servitude. As she struggles to keep her spirits up, she makes some remarkable discoveries that may change her seemingly bleak fate.