The Women's Historical Society believes that the hero of the Revolutionary War's Battle of Mayberry Bridge has a direct descendant living in Mayberry. Two members of the Society, Harriet Bixby and Mrs. Wicks, set out to discover who Nathan Tibbs' descendant is so that they can award him or her a plaque. As the two ladies scour the Mayberry archives in search of this unknown "hero", there is rampant speculation about just who it might be.
Barney does a bit of research at the town library and becomes convinced that he is the descendant of Nathan Tibbs - even going so far as to write a "humble" acceptance speech. When it's revealed, much to the chagrin of the mayor and the town council, that the famous relative is none other than Otis Campbell, the town drunk, Mayberry's officials panic. Mayor Pike, convinced that Otis will shame both himself and the town, orders Andy to find a replacement and keep Otis away from the award ceremony. However, after talking with him, Andy realizes that despite his bad habits, Otis considers it an honor to represent the town and cherishes the opportunity to see his wife, Rita, "as proud as a peacock".
When Otis is a few minutes late for the ceremony, Andy confesses that he did not find a replacement. Barney and the Mayor immediately fear the worst, that Otis is drunk and will show up and embarrass the whole town. However, when Otis shows up a few minutes later with his wife, he is sober, clean shaven and wearing his finest suit. He accepts the plaque, not for himself, saying "Shucks, a man can't take credit just for bein' born", but on behalf of the town of Mayberry - handing the plaque to a surprised Mayor Pike.