A Little Princess by Frances Hodgson Burnett
Sent to an English boarding school from her home in India, privileged Sara Crewe becomes a show pupil - a little princess with luxuries bestowed upon her because of her father's wealth. But when her father dies, Sara's whole life is turned upside down as she is transformed from princess to pauper. Abused by Miss Minchin, the spiteful headmistress who treats her like a slave, Sara finds protection in her imagination and sisterly love in her friend Becky. As she struggles to hold on to the memory of her beloved father, Sara learns that strength doesn't come from wealth - it comes from love. After all, real little princesses are made with kindness.