"Here Comes The Brides" (5Dec1977) Little House on the Prairie S04×E12

Adam & Luke Simms move to Walnut Grove. Luke falls in love with Nellie. Nellie likes him but he doesn't like to wear shoes and he wears overalls without a shirt over his long underwear, so Harriet thinks he is beneath her and demands that Nellie stop seeing them. Luke gets Mary to help him pick out a ring for Nellie's birthday and Nellie thinks Luke was playing with her affections. Nellie cries to Miss Beadle and Miss Beadle goes to Mr. Simms to tell him that she won't have that kind of treatment in her school. Mr. Simms explains the situation and Miss Beadle starts to fall in love with Adam Simms. Luke and Nellie decide that they are going to elope. They get married and go to the hotel. That is where Harriet, Nels, Adam, and Ms. Beadle find them. They take them back to the Justice of the Peace and have him un-marry Luke and Nellie, but while they are there, Adam Simms and Eva Beadle get married.