Thirteen-year-old Hannah Bennett loves her life in Chadds Ford. She goes to school, helps out with her family's dairy farm, jumps rope, and listens to favorite radio programs with her friends. Although she has difficulty reading, she does have one area of special talent: numbers. Her gift for math means that she does all of the invoicing for the farm, and helps out the younger students in their one-room schoolhouse. Best of all, Hannah enjoys a special relationship with Granddad McNaughton, who shares her passion for counting and calculating. He thinks of her gift as the key to a greater future elsewhere. 'You'll rust here,' he predicts. But Hannah can't imagine life anywhere else. Then Hannah is offered a rare opportunity for a country girl in 1934: to test for a scholarship to attend a private school in Philadelphia.