The school's new teacher is Ms. Wilder. Laura falls in love with Ms. Wilder's brother Almanzo. Laura is crushed when Nellie invites Almanzo over for dinner. Laura gets even with Nellie by volunteering to cook dinner for them. Laura adds some hot spices to the chicken and since Nellie had said that she had cooked the meal, Almanzo stays away from Nellie.

When Laura and Nellie get in a fight about the graduation test, Almanzo separates them and takes Laura home with him. When Charles finds out that Almanzo took Laura home with him, Charles goes to Almanzo's place and punches Almanzo because he fears his daughter was being taken advantage of. Laura yells at the fighting pair and tells them that she is no longer a child.

Each student must trace their family tree for a school assignment. Albert is unsure how he can do the assignment. The Ingalls decide to legally adopt Albert, but run into problems when Mr. Quinn, Albert's father shows up. He wants Albert until he sees him. Albert pretends to be blind with the hope that his father wouldn't want him. The blindness does the trick. Albert is legally adopted by the Ingalls.

Adam wins a prestigious award. Laura and Albert give the Christmas money they had made from collecting honey, to Adam and Mary to go on a trip to receive the award. The stagecoach is involved in a very serious accident.

A circus comes to Walnut Grove. Everybody is helping set up, except Nels Oleson. His long, lost sister is in the circus. Only Mrs. Oleson believes her husband's story about his sister. Nels is nominated to be the announcer at the circus. When he announces his sister, he says, ""My sister, Annabelle."" These words lead to Nels and Annabella becoming very close siblings.

Mrs. Craig is in love with Reverend Alden. Although Mrs. Oleson tries to stop Reverend Alden from marrying Mrs. Craig, the wedding goes on as planned.

Albert's imagination starts to get the better of him when he dreams that he and Laura are taken by Indians.

When Isaiah Edwards loses his will to live after a crippling logging accident, a letter to Walnut Grove from his worried wife, Grace, brings Charles and Laura back to the big woods to try to help their old friend.

Aging professional wrestler Milo Stavroupolis comes to nearby Mankato to "fight" the locals. Stavroupolis' promoter, the shrewd Jimmy Hart, convinces Jonathan Garvey to fight the old man ... unaware that the fight was "fixed." But there's even more heartbreak ahead, as Stavroupolis is suffering emotionally (and physically) after years of fighting; his beloved wife, Anna (herself desperately ill) has begged him to retire. The old man is convinced by Jonathan to substitute for him in the upcoming championship

Mrs. Oleson invites a charismatic preacher, the Rev. James Danforth, to preach in Walnut Grove. He immediately woos parishioners away from Rev. Alden's congregation with his fiery sermons and "faith healing." But nobody is aware he is a charlatan, and it will soon have tragic results.

During a trip to Walnut Grove, Caroline's mother passes away. Her father is very grief-stricken, until son-in-law Charles - impressed with his stories about growing up in the Little House in the Big Woods - suggests he publish an autobiography.

The telephone comes to Walnut Grove, and Mrs. Olesen is hired as the switchboard operator. She takes advantage of her responsibilities to engage in her favorite pastime: gathering gossip. It will have a very damaging effect on the Garveys' marriage when she learns about Alice's hidden past.

A 17-year-old budding criminal named Tod Dortmunder is sent to Walnut Grove to live with his grandparents after his mother loses patience with his ill-tempered behavior. His behavior becomes more violent, and when he is caught stealing Charles' watch, the grandparents (in part because they fear for their safety) turn to Charles for help. Charles proves to be the role model Tod never had, and efforts to rehabilitate the lad seem to be working. But even Charles is unaware of some dark secrets from Tod's childhood that don't surface until he destroys the present he gave him.

School bully Bart begins menacing his classmates, especially Albert. Tired of the constant harassment, Albert creates a paper maché werewolf mask to terrorize Bart into ceasing his bullying behavior. It works, until Carrie opens her mouth! It takes a joint effort by all of Bart's classmates to make him stop bullying.

During a visit to a farmer's convention in Milwaukee, Charles and Caroline meet up with old school mates. Charles learns that larger farmers are trying to put his small farming friends out of business and urges them to stand up for their profession. Meanwhile, Caroline becomes envious about the financial fortunes of their one-time friends, but she soon learns there's more to their success stories than meets the eyes.

On a dark and stormy night, Laura and Mary are staying alone at the School For the Blind when they are taken hostage by a trio of escaped convicts. One of the criminals is badly injured, and his cohorts demand to see a doctor. Laura is sent to get Dr. Baker, warned that the consequences will be deadly if she tries any tricks. However, a terrified Laura tells her Pa what is happening. Charles shows up posing as Dr. Baker, but when the real Dr. Baker arrives, Charles is forced to be resourceful to disarm the crooks.

Albert experiments with smoking in the basement of the School For the Blind and, when shooed out of the basement, hides the still-lit pipe in some cloths. It ignites and results in a late-night fire that kills Alice Garvey and Mary's baby son. As a result, several people struggle with the consequences: Albert becomes withdrawn when he learns his careless actions may have caused the fire, Mary in deep shock and Jonathan Garvey in an alcohol-induced state of denial. Albert, Mary and Jonathan - all deeply impacted by the fire at the school - continue to deal with their emotions. Charles helps Jonathan realize that his alcoholism has taken a toll on his son, Andy, while Mary snaps out of her shock when she hears the melody of the music box Albert had purchased for her as a gift. Albert panics when he finally understands his carelessness caused the fire that killed Mary's baby and best friend's mother. He runs away, leading Charles and a reformed Jonathan to frantically search for the lad.

Almanzo's indolent brother, Perley, comes to town. Knowing that Almanzo's interest in a much younger Laura has deepened, Charles is convinced that Perley is the better man for his "Half Pint." However, those sentiments quickly change when Perley injures one of Almanzo's horses. Two things become clear to Charles: Perley is a troublemaker, and Almanzo is a responsible young man (especially when he nurses the horse back to health).

Nels finally loses patience with his henpecked family life and begins a mobile merchant business. During one of his stops, he meets a much younger woman whom is the exact opposite of his own wife. In the process, Nels struggles with temptation and going astray as the relationship blossoms.

The school district's superintendent comes to Walnut Grove, looking for someone who can replace a teacher who has fallen and broken her leg. Eliza Jane recommends Laura. Almanzo thinks he has no chance of Laura falling in love with him.

Almanzo asks for Laura's hand in marriage. Mr. Ingalls tells Almanzo to wait until Laura was eighteen. Not wanting to wait, Almanzo forces Laura to choose him or respect her father. Laura respects her father's wishes. Almanzo leaves town and causes Laura a lot of heartache. Harriet hires Percival Dalton to help her in the restaurant. Nellie and Percival fall in love and eventually Percival asks Nellie to marry him. Adam's father dies, which means that a new blind school wouldn't be built in Walnut Grove.

Laura helps Adam and Mary set up a new blind school in Sleepy Eye to try to get her mind off of Almanzo. Almanzo gets very sick.