A college-educated farmer named Joe moves to Walnut Grove with his pregnant wife. He tells the Walnut Grove-area farmers of a new hybrid of corn that would produce good crops, to which the farmers are very enthused. They decide to buy some of this new seed. While on the way back to Walnut Grove with the seed, Joe gets into an accident, as the farmers wait for his return.
Believing that her jealousy was responsible for her infant brother's death and that her parents would rather have a son than a spare daughter, Laura climbs the highest hill she can find, hoping to get as close to God as possible to ask Him to take her instead and return the baby boy to the family. While Charles and Mr. Edwards desperately search for her, Laura meets Jonathan, a mystical mountain man who seems to have been sent purposely to guide her through this life-changing experience.
After Ms. Beadle sprains her ankle, Caroline becomes the substitute teacher. Caroline takes a special interest in helping an older student, Abel, learn to read. One day Mrs. Oleson shows up and causes Abel to quit school. Because of this Caroline quits, but returns after she convinces Abel to give school another chance.
Laura falls in love with a new student, Johnny Johnson. Johnny, who is a lot older than Laura, is interested in Mary instead. Although Mary is not interested in Johnny, Laura's actions cause tension between the sisters. When Charles finds this out, he is appalled that either of his girls is involved with Johnny.
While Charles is in Mankato, he runs into Mr. Edwards and invites him to come to Walnut Grove. Caroline tries to match Mr. Edwards up with Grace Snider, but instead she just ends up in the way since Mr. Edwards is able to charm Grace all by himself. Although there are a couple problems that must be overcome, things turn out for the best in the end.
In the beginning, things look very good for the Ingalls until a bad hailstorm ruins their crops. Charles and some other farmers must leave to look for work. They end up working in a quarry. While Charles is away, Caroline is able to get the women of Walnut Grove to join together to harvest the remaining crops.
Laura and Mary start school for the first time. That is where they meet Nellie Oleson. Since Laura hasn't been to school before, she tries especially hard with her schoolwork. The students have to write an essay to present in front of the class. Laura recites what she would have written on the paper if she could have, instead of what was actually written on it.