Charles and Caroline sign Mary up for the blind school in Iowa. At first, Mary is very reluctant to learn anything at the school. However, after being with her teacher, Adam Kendall, for a while, she turns her outlook on life around. Mary is such a great student that Adam asks her to help her teach at a blind school with him.
Mary falls in love with Seth. When Mary's eyesight starts to get worse, Charles takes her to a specialist. He is devastated when the specialist tells him that Mary will lose her sight. Charles is unable to tell Mary for a while that she is going blind. When Mary does go blind, the whole family suffers.
Mrs. Olesen may finally get to drive those ""homely"" Ingalls from Walnut Grove for good when the family gets an inheritance from a wealthy relative. Against their better judgement, Charles spends the money on farm equipment and other things before finding out he used worthless Confederate funds to make the purchases.
When Laura is playing along a creek, she finds a bottle with a note in it. The note read, ""Be my friend."" Laura convinces Pa to help her look for the person who sent the note. They end up finding a baby. Charles then searches for the parents of the child. The baby belongs to teen parents. The reason the mother left the baby for the Ingalls to find was because her dad was opposed to her being with the guy she conceived the child with. The young parents take the baby and try things again.
Mr. Ingalls is severely delayed when a wheel breaks on his wagon in the pouring rain. This is the day of Charles and Caroline's wedding anniversary. Everything had been all prepared and set up for that day. When Charles doesn't show up in time, Caroline tells the children how hard it was to get Charles to notice her and how many heartbreaks she had before she finally knew that Charles loved her.
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.