It's the first day of school for Mary and Laura but Laura doesn't want to go and her Pa has to coax her into going, telling her that he made a promise to Ma. He tells her that she will like school. After the girls pass inspection, Ma gives them her old school books and they head out for the walk to town and school. Mary has to keep reminding Laura to hurry.
At the school the girls approach the kids playing where the kids tease them and call them snipes as the bell rings and they file into the school. Nellie calls them "Country Girls." At the door, Laura and Mary hesitate until Miss Beadle, the teacher spots them. She welcomes them to the school as Laura glares at Nellie. As the girls don't have a writing slate, Miss Beadle loans them hers. Laura is ridiculed by the class and Nellie in particular at the concept of a blackboard.
At home that night, Laura shows her father what she has learned, how much she likes Miss Beadle and how much she hates Nellie Oleson. Pa hands Laura a dime to buy a slate and some paper for tomorrow. Charles wonders why Laura is so feisty about Nellie but he has met her mother--a pleasure Caroline has yet to experience.
The next day, Mary and Laura stop at Oleson's to buy a slate and tablet but don't have any money for a slate pencil. While there, Nellie and Willie come down teasing the girls. Mr. Oleson offers to give them a slate pencil but they refuse. Mary decides to use her Christmas penny to buy a pencil. Miss Beadle helps Laura with her reading.
At the brook by the house, Laura practices what she's learned. "If I had a remembrance book, there's one thing I'd want to put in it about school. Ma and Pa were right: It was fun. Especially when all the different letters starting turning into words. But learning to write was one of the hardest things I'd ever hoped to do. Recess was supposed to be the most fun, only Nellie Oleson wouldn't ever let us play anything but Ring Around The Rosie. I didn't want to, but Ma said, "Do unto others..." I couldn't help wondering if Nellie's ma would get around to telling her the same thing."
Caroline takes 3 dozen eggs to sell at Olesons and is waited upon by Mrs. Oleson who offers her 4 cents less per dozen for brown eggs. At home that evening, Caroline is stewing about her run-in with Mrs. Oleson and tells Charles. Charles offer to intercede with Nels but Caroline refuses as Charles reminds her of her credo, "Do unto others..."
At school the next day, Laura rebels at playing the same old games and after Nellie pushes her down three times, Laura knocks Nellie down. That night she apologizes to Ma and Pa and promises to not do it again but adds she won't have to because Nellie is now afraid of her.
Caroline takes another batch of eggs to Oleson's. Mrs Oleson scolds her about the fight Laura started with Nellie at school the previous day but Caroline observes that Nellie obviously has her own version of the events. Mrs Oleson interrupts her stating that brown eggs are still 4 cents less per dozen but Caroline has brought only white eggs to sell, telling Mrs Oleson that she sold the brown eggs at Hanson's. When Mrs. Oleson tells her she can sell her white eggs there too, Caroline agrees and starts to walk out but Mrs. Oleson stops her and tells her that she will buy all her eggs at the regular price. Caroline attempts to buy some pricey fabric but Mrs. Oleson repeatedly tries to sell her a plain coarser material before Caroline points out that the customer is always right. That evening she realizes that Mrs. Oleson goaded her into buying the more expensive fabric and decided to take it back until Pa and the girls convince her otherwise.
"Ma gathered enough eggs to walk us into town two or three times every week. Sometimes, she'd tell us about when she was a little girl. I tried scrunching her down in my mind, so as I could see her all barefoot, pigtails flying but it never did work. She kept right on being ma, which was all right, since we loved her a whole lot, just the way she was. Arithmetic was easy. I liked reading most of all, but writing...I didn't I'd ever learn to put down big words the way Mary did. Not even with Ma to help me."
Mary and Laura excitedly tell Ma and Pa about the school's Visitors Day scheduled for Friday. The kids have to write essays and present them to the class and their parents. "Ma and Mary and me worked hard and steady that whole week. But before we knew it, time was up. Visitors' Day was the next morning. Ma's dress was pretty near done and so was Mary's essay." Mary's essay was about her Pa and how he brought them from the Big Woods to Kansas to Plum Creek. Laura is troubled because she can't get the big words in her head down on paper and scared about talking in front of a crowd.
As the kids sleep, Charles wakes up to find Caroline is still working on something in the living room. The next morning, Mary and Laura are surprised to find that Ma has turned her new dress into new dresses for each of them. At school, Willie is giving his essay on horses. Nellie gives her essay on her lavish house. Laura gets up and gives her essay, a heartwarming tribute to Ma. Leaving the school, Nels Oleson congratulates Charles on his family. Caroline thanks Laura for her essay but tells her that wasn't what she wrote on her paper. She takes Laura back into the school to fess up to Miss Beadle. When she hands her her essay, it has only four short lines on it. She ignores it and instead gives Caroline a summary of Laura's strong and weak points in school.
"Ma took Mary's essay and mine too. She said she was going to put them in the special box where she kept the schoolbooks and her wedding dress and everything she loved most. Made us proud that she'd want them for remembering, but I knew even without the papers, there wasn't one of us likely to forget that day. Not ever."