A new boy, Luke Simms, starts school in Walnut Grove. Nellie takes an interest in Luke immediately. Nellie wants to invite him over for dinner, but her mom, is not sure if he is good enough to have dinner with the family. Nellie tells her that Luke's father sold a big farm in Illinois and will be investing in a farm in Walnut Grove. Harriet is intrigued and allows Nellie to invite Luke over. The whole family gets dressed up and is shocked when he comes in without dressing up and without shoes. The whole family except Nellie cannot believe how bad his manners are and Harriet throws a fit after he leaves. She then forbids Nellie to see him again, but Nellie says that she does not care and continues to see Luke. She tells her parents that she is going to her room to study, but sneaks off to see Luke. Mrs. Oleson catches both of them on the porch and decides to talk to Ms. Beadle about stopping them from seeing each other. She asks Ms. Beadle to talk to Mr. Simms and Ms. Beadle agrees perhaps because she is interested in Mr. Simms. He tells Ms. Beadle that he doesn't see the point in stopping two kids who like each other from seeing each other. She agrees and they begin to talk and he asks her to call her by his first name, Adam. She agrees, but only if he calls her by her name, Eva. The next day at school Nellie sees Luke go off with Mary and becomes jealous Luke takes Mary into the store and he buys a ring. Nellie finds out and becomes upset. Ms. Beadle comes out to the Simms farm to scold Luke about hurting Nellie, but finds out the ring that he bought was actually for Nellie. Ms. Beadle and Mr. Simms end up talking and make a date to go to the corm shucking together. Upset over Luke, Nellie decides to stay home instead of going to the corn shucking with her family. Luke shows up to take Nellie to the shucking and also gives her the ring that he bought with Mary. Nellie realizes that she misunderstood the situation and they leave to go to the shucking, but along the way steal a kiss. Ms. Beadle, Mr. Simms, Nellie, and Luke continue to spend time with one another with affections growing on both sides. Mr. Simms asks Ms. Beadle to marry him, and she is taken aback, and he tells her to take time to think about it, because he wants her to be sure. Luke and Nellie see his father and Ms. Beadle and he asks Nellie if she will Mary him. She says she is not sure and that she will have to think about it. Nellie decides to ask Ms. Beadle what she thinks. Ms. Beadle convinces Nellie to marry Luke inadvertently thinking that Nellie is talking about her relationship with Mr. Simms. Later, Ms. Beadle tells Mr. Simms that she will marry him. Luke and Nellie leave to get married and Mr. and Mrs. Oleson find out from Willie and head off to the Simms farm. They talk to Mr. Simms and Ms. Beadle and they all figure out that they are headed to get married. All four get in the wagon and head off to stop the wedding. In Sleepy Eye Luke and Nellie get married and go to find a room. They find the Justice of the Peace and find out the kids have already been married. They break off to go to find the kids at the one of the hotels. At the room Nellie and Luke try to get past the uncomfortable first moments alone together. Mr. and Mrs. Oleson find the two and Harriet tries to shoot Luke. They bring the kids back to the Justice of the Peace to unmarry the kids. He rips up the marriage certificate and declares them unmarried. Mr. Simms and Ms. Beadle decide that this is as good a time as any to get married. They are married with Nellie as the maid of honor and Luke as the best man.