Thirteen-year-old Rosie Beckett has never strayed further from her family's farm than a horse can pull a cart. Then a letter from her Aunt Euterpe arrives, and everything changes. It's 1893, the year of the World's Columbian Exposition-the "wonder of the age"-a.k.a. the Chicago World's Fair. Aunt Euterpe is inviting the Becketts to come for a visit and go to the fair!