O Pioneers! tells the story of the Bergsons, a family of Swedish immigrants in the farm country near the fictional town of Haver, Nebraska, at the turn of the 20th century. The main character, Alexandra Bergson, inherits the family farmland when her father dies, and she devotes her life to making the farm a viable enterprise at a time when other immigrant families give and leave the prairie. The vel is also concerned with two romantic relationships - one between Alexandra and family friend Carl Linstrum, and ather between Alexandra's brother Emil and the married Marie Shabata.