"Nancy and Plum" is a children's book written by the world famous author Betty McDonald, who wrote four popular "Mrs. Piggle Wiggle" children's books, and also the adult books, "The Egg & I", "Anybody Can Do Anything" and "Onion in the Stew".

"Nancy and Plum" was first published in 1952. It is a story Betty told her daughters, Joan and Anne, each night at bedtime, making it up as she went along. It is a delightful old fashioned Christmas story about two sisters, Nancy, 10 and Plum, 8, whose parents died in an accident. Their surviving relative is Uncle John, a wealthy bachelor with little patience or time for children. He puts the girls in Mrs. Monday's Boarding School in Heavenly Valley, persuaded by Mrs. Monday's promises and unctuous manner, but she is a mean spirited woman who mistreats the children in her care (except her spoiled niece Maribelle). The sister's devotion to each other and their steadfast moral character wins them support from teachers at school and helps them secure a new and better future after various adventures.