Nancy and Plum — Betty MacDonald

It was Christmas Eve. Big snowflakes fluttered slowly through the air like white feathers
and made all of Heavenly Valley smooth and white and quiet and beautiful.

So begins the story of two orphaned sisters at Mrs. Monday's Boarding School. But nothing is heavenly for Nancy and Pamela (aka Plum): their parents died in a tragic accident years ago, they're constantly punished by the cruel Mrs. Monday, and they're all alone for the holidays.

Luckily, Nancy and Plum have each other, and though their prospects may be bleak, they're determined to change their lot for the better. If their plan works, the spirited sisters will never spend Christmas at the cold, dark boarding school again. But what will they find on the other side of Mrs. Monday's gate?