While studying for an optional history exam in the barn, Mary accidentally knocks over a reading lamp and starts a fire. Caroline punishes Mary by telling her she couldn't take the exam. Mary doesn't tell Ms. Beadle this until the day of the exam.

Caroline becomes pregnant. Shortly after the baby is born, he becomes ill.

Several people in Walnut Grove get very sick. A quarantine is set up in the church while the source of the illness is being sought.

After Julia Sanderson's death, her three children stay with Grace, with help from Mr. Edwards. When Charles is unable to find someone to adopt all three children, he has to make the difficult decision to place them in separate homes. At the very last minute, Mr. Edwards makes a monumental decision: he marries Grace - and they take on all three children.

Nellie falls off of Bunny and pretends to be paralyzed. Mrs. Oleson blames Laura for this and wants to destroy Bunny.

Charles' father, Lansford Ingalls, doesn't want to live after his wife dies. Charles brings his father to Walnut Grove to help him out. When Laura's horse gets hurt, she blames her grandpa.

Lansford leaves because he feels really bad. Once Laura realizes that her grandpa wasn't to blame for the accident, she looks for Lansford and convinces him to come back home.

A mother is in deep denial over her daughter's death in a tragic drowning. To comfort herself, she kidnaps Laura, hoping she will take her late daughter's place.

People in Walnut Grove are betting on a big boxing match in town. Mr. Ingalls does not know that he will be fighting an extremely sick person. That's why Charles is surprised in the ring when he is able to defeat his opponent so quickly. After his opponent collapses, he is brought to Doc Baker. Doc Baker is able to save him but warns him that he needs to stop fighting.

Poor economic conditions cause the Ingalls to move closer to Mary. Mary is now teaching at the blind school. The Ingalls move to be closer to Mary, where she helps teach the younger blind students. Laura catches an orphan, Albert, stealing from their hotel. Charles becomes friends with Albert and invites him to Mary's birthday party.

Charles even sells his fiddle to buy Mary a gift. At the party, Mary gives Pa his fiddle back. Laura gives Mary a card. Mary is so proud of Laura writing the letter in braille. Almost everyone is in tears, including Mrs. Oleson, when Mary announces that she has nothing to wish for, since she has everything that she could possibly want.

Amelia, a new girl that Laura meets in school, is ashamed of her very overweight father. Her father works at the blind school where Mary works. All the blind students like him a lot. They claim that they can see his love. One day, Laura and some other students from school, start making fun of the overweight person, not knowing that they were making fun of Amelia's father. Amelia's father pretends to leave town since his girl is so ashamed of him. He hides out at the blind school. When he is involved in an accident, Amelia reveals to her dad how much she loves him.

Toby Noe wins a lottery of $5,000 and becomes a man of means. He buys the children a cartload of fireworks, for an annual celebration. Standish dupes Toby into losing all his money using cards and drink at the saloon. Everything comes to a head as the fireworks go off in the saloon. The Ingalls, Olesons, and Garveys get tired of the bustling city life during all this (Nels getting drunk and wins a whole pile of money), and they decide quickly to return to Walnut Grove. The Ingalls take Albert along with them.

As the Ingalls, Garveys and Olesons return to Walnut Grove they discover a town that is badly in need of repair. With a lot of hard work, from everyone around them, they're able to get the town back to its old self, helping a number of people who feel they are living in a dead town, like Lars Hanson.

Charles stays with a family while looking for some horses to buy. The children of the family asks Mr. Ingalls if he could possibly do something to keep their parents from splitting up. Thanks to Charles talking to the husband and the wife, they decide to stay together and work things out.

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.

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

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.

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 purchases some land and hires Harv, a friend of his, to help him in the field. Almanzo soon learns that he was tricked into buying the land. He is unable to get any justice. This causes Almanzo to call off the wedding until he gets back on his feet. Laura gets a teaching position, but Almanzo doesn't want her to work. Laura decides to take the position anyway.

Eliza Jane falls in love with Harv, but is afraid to tell him how she feels. Eliza Jane is devastated when she finds out Harv has somebody else in his life. Since Eliza Jane doesn't want to see Almanzo and Laura break up, she decides to leave and tells Almanzo to chase after Laura to tell her that she could teach in Walnut Grove. Laura and Almanzo then get married at the blind school.

A story of fear (for the brothers), heartache and love. Houston, an old man, takes care of two runaway orphans. The orphans were running away because the orphanage wants to separate them. Houston talks to the adopting parents and convinces them to take both of the kids.

A blind person has a talent for painting. Her work is so good, it soon gets publicized. The person's biological mother comes and tries to make up for what happened in the past. Only after the blind person learns that her mother abandoned her so that she could have a better life did she agree to see her mother.

Albert begins writing more frequently to a pen pal of his. He tries to impress the girl he is writing to. The girl also does the same thing. Albert falls in love with her and goes to see her one time. This girl is very reluctant. Albert thinks that she doesn't like him until he sees her in a wheelchair. Both of them promise to continue writing to each other, but this time they would only tell the truth in their writings.

Adam makes a decision when his sight returns, after an accident at Jonathan's freight warehouse. Mary feels that Adam may be slipping away from her.

Adam goes for his test and hopes to get a scholarship. But far away from home, he is robbed and beaten and after racing to continue his test (2nd part), he catches a fever.

A schoolyard escapade involving Albert brands 15-year-old girl Sylvia a tease. The two fall in love, but Albert is unaware of a number of circumstances which have thrown Sylvia's life into a frightening tailspin - getting raped by an unknown assailant and the girl's domineering father.

A pregnant Sylvia finds Albert is the only one she can turn to for solace, since her father blames her for her situation. Albert and Sylvia decide they want to elope so she doesn't have to move with her father, over both their parents' objections.

Percival and Nellie go to New York so that Percival can run the family business now that his father has died. Mrs. Oleson gets very depressed because of Nellie leaving. The Olesons decide to adopt a girl to take the place of Nellie. While they are in Sleepy Eye, they find a girl that looks almost exactly like Nellie when she was young.

Nancy turns out to be worse than Nellie ever was. She even locks another girl in the ice house. The students devise a plan to teach Nancy a lesson. They trick her into being the star in a dunking tank. Also during this episode, Adam and Mary move to New York so that they can earn a living and Hester Sue comes to Walnut Grove to work at the restaurant.

When Charles refuses to admit that James will likely never recover from his gunshot wound, he leaves Walnut Grove with his adopted son. He builds an altar in the woods and hopes that God will bring a miracle.

The Ingalls are forced to sell their house to the Carters and leave Walnut Grove to find a more promising life. Mrs. Carter begins printing a newspaper for Walnut Grove. Etta Plum becomes the teacher in Walnut Grove when Laura decides she wants to spend more time with Rose. Almanzo's brother, Royal, comes to Walnut Grove with his daughter, Jenny.

Royal has a very bad heart and asks Laura and Almanzo to take care of his daughter since he was going to die soon. Jenny is devastated by her father's death. After talking to Reverend Alden about heaven, she tries to commit suicide by drowning so that she could be with her father again. Jeb Carter is able to save Jenny although he can't swim. Laura convinces Jenny that she should do what would make her parents proud.

A tiny circus performer, Lou, decides to look for work in Walnut Grove after his wife dies while giving birth to his baby girl. A prejudice Mrs. Oleson uses her power to make sure that the dwarf doesn't find work. She even threatens Mr. Anderson that she would close her account at the bank if he hired Lou. To keep the infant alive, the dwarf must steal food. Mrs. Oleson decides to press charges when she finds out who stole the food. When Nancy falls in a well, Lou risks his life to save the girl. That's when Mrs. Oleson decides that being small has its advantages and decides to drop all charges.

Jenny looses a necklace in a pond and almost drowns trying to get it. After the incident, she has partial brain damage and has to retrain herself to talk and walk. Jenny's friend, a retired doctor, helps Jenny to force herself to get better. Thanks to him, Jenny makes a complete recovery.

The Older Brothers is a gang that used to have a notorious reputation. First they hold up Mr. Edwards but end up losing the money. Then they try to get ransom money for Mr. Edwards but that doesn't go very well.

When Albert continually breaks the law, Charles takes him out of the big city and back to Walnut Grove. Albert doesn't change in Walnut Grove because he is addicted to morphine. Charles finally forces Albert to stop using morphine. He stays with Albert while he goes through withdrawal. Thanks to Charles, Albert is no longer addicted to morphine. We find out at the end of the show that Albert will become Dr. Albert Ingalls.

Laura gives birth to a baby boy. The baby is fine and healthy for a while. Then for no apparent reason the baby dies. To ease her mind of the death, she blames Doc Baker for what happened to her baby. Doc's reputation declines so much that he must leave town to find work. Just before Doc Baker leaves, Rose comes down with small pox. Doc must stay quarantined with the Wilders for two weeks. Watching the Doc save Rose's life causes Laura to rethink her attitude about Doc Baker. Laura and the rest of the town convince him to stay on.

No longer a mama's boy, Willie announces his engagement and plans to marry his sweetheart. All this upsets his mother greatly, who makes several attempts to get her way.

Charles and Caroline visit Walnut Grove and are pleased to be able to stay in the 'Little House' when John and Sarah Carter go out of town. Then the townspeople learn that a land development tycoon, Nathan Lassiter (James Karen), has acquired title to all the land in Hero Township, which they had believed to be homesteading land. Having failed to defeat his claim on legal grounds and even with guns against an army cavalry unit, the townspeople are inspired by Laura to vent their anger at what they see as an injustice, and they decide upon a drastic plan of action. When Lassiter arrives to claim the town, he finds all the town buildings dynamited, and the townsfolk leave to start new lives elsewhere, as many of them have done before.