In the summer of 1873, Per Hansa, his wife Beret, their children, and three other Norwegian immigrant families—Tonseten and his wife Kjersti, Hans Olsa and his wife Sorine, and the Solum brothers—settle in the Dakota Territory. Per's family becomes lost when they separate from the other wagons, but they eventually reache their destination. They establish a small settlement along Spring Creek, and everyone starts building sod-houses.
A man of action, Per thrives in the work of building a home for his family on the prairie. He dreams of the day when he will be wealthy and own a lot of land. However, his sensitive wife, Beret, does not adapt very well to life on the desolate prairie, and she begins to feel homesick for Norway.
The settlers meet many threats on the prairie, but they persist, striving to build a new life. Per encounters a band of Indians, but they prove to be friendly. Next, the settlement's cows disappear, but Per manages to find them. Per meets his greatest challenge when he discovers stakes that earlier settlers placed in the land to claim it—but he removes them. When the Irish settlers return to reclaim their holdings, they can find no trace of their markers. Though Per has saved his neighbors' land, Beret discovers to her horror that Per has committed the crime of removing another man's landmarks. Beret feels uncivilized living in the wilderness— she wants to return to Norway. Whenever Per leaves her to go to town for supplies, she feels lonely. Per attempts so brighten things up, surprising everyone by whitewashing the interior of his sod house. However, nothing can cheer Beret up as she gradually sinks into depression.
As Beret approaches childbirth, she becomes increasingly difficult. Per hopes that she will return to her normal self when she has her baby. As winter falls, however, Beret grows more and more desolate. She begins to think about her past in Norway and about all of the sins she has committed. She also remembers how she first fell in love with Per. Beret regrets defying her parents' wishes by moving to America. On Christmas Day, she begins to go into labor, and Per fears that she will not survive. However, she survives and gives birth to a son, whom Per names Peder Victorious. Per makes Hans Olsa baptize the baby.
The winter proves lonesome for many of the settlers, who amuse themselves with social gatherings. Henry Solum organizes a school for the children. The settlers begin to run out of supplies, so the men of the settlement decide to make a trip to town. Per almost dies when he is caught in a storm, but he reaches safety when he finds a house. Later, he discovers a way of making money by trading furs with the Indians. On another occasion, the immigrants decide to adopt American names. Only Beret feels that these names are sacrilegious steps away from their Norwegian fathers.
More and more caravans pass through the territory. One day, a strange Norwegian couple arrives with a tragic story. The wife, Kari, is insane with grief because her son died and had to be buried in the prairie. While Beret grows more and more unhappy, Per thrives as summer passes and his crops prosper. Per continues to be optimistic despite all the hardships they face, and he dreams of one day providing a better life for family. However, one day the settlers see their crops destroyed by a plague of locusts. Per's crops are saved, but his wife is missing. He finds her hiding in her emigrant chest, insane with fear. For the first time, Per is helpless because he cannot make his wife better. He is horrified to see his beloved Beret deranged.
Several years pass. As new settlers arrive, the community grows. Beret eventually becomes obsessively religious after she falls under the influence of a traveling minister, who baptizes Peder Victorious and then stays on in the community. Beret begins to regain her senses with the help of the minister and Per. Per and Beret's relationship remains distant, however.
The winter of 1880–1881 proves to be especially harsh. Hans Olsa, the friend and neighbor of the Hansas, becomes severely ill. Beret feels concerned about Hans's spiritual well being, and she insists that Per fetch the minister to be with the dying man. Per and Beret have a fierce argument. Reluctant because he knows the trip is impossible in the severe weather, Per at last agrees. On the journey, he is caught in a fierce blizzard and dies alone on the prairie.