Their only 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 Mrs. Monday is an ogre who pampers her niece, Maribelle, and persecutes the other girls in her custody. Of the two sisters, Plum is the spunky one, leading Nancy on forays for food and initiating their running away. There are lovely characters who are sympathetic and help the girls: Mr. and Mrs. Campbell, who find the girls on their farm and rescue them; Miss Waverly, the school teacher; Miss Appleby, the librarian, and Old Tom, the caretaker at the orphanage.