The wealthy and handsome Captain Crewe deposits his beloved daughter Sara at a London boarding school. The stern headmistress of the school, Miss Minchin, resents Sara from the first day of class. But not only is Sara clever, she is also uncommonly good, and gifted with the ability to tell stories that win her a fiercely devoted group of followers and the nickname Princess Sara. During Sara's birthday party, Minchin discovers that Captain Crewe has died of brain fever and left Sara penniless. Enraged, Minchin strips Sara of her finery and forces her to become a maid-of-all-work. Sara invents a fantasy-life she calls "the magic" that warms her despite the bitter cold. Someone leaves her secret gifts that make her believe ever more strongly in the magic. Her benefactor is the school's mysterious new neighbor -- Captain Crewe's business partner, who has been searching the globe for little Sara. He adopts her, and she becomes Princess Sara once again.
It's ok to start your synopsis a little further into the story than the manuscript does, if the problem comes later. You couldn't skip over the very beginning of Hatchet, of course. But here, the beginning is all prologue to Sara's fall from privilege and how she makes the best of it-- with goodness, imagination, and spirit-- and how she finds a happy ending in spite of her misfortunes and enemies. For a short synopsis, start with the problem.