S4, E11: The Ingalls and Oleson families spend a fun-filled and exciting day at a county fair. Sparks fly between Mary and a smooth-talking balloonist, Caroline and Harriet face off in a pie-baking contest, and Charles and Nels enter a gritty competition of their own. Laura wastes all her spending money in a surprising way, and Carrie faces serious danger when Laura fails to supervise her.