This episode is one of many in Season 4 that helps bridge the character of Mary Ingalls into adulthood. An opportunity to temporarily teach in a nearby community presents itself, and Mary eagerly accepts, only to find that everyone in the town is under the "spell" of Miss Peale, a spooky, shrieking religious fanatic, who objects to everything about Mary, from the way she dresses and speaks to the subjects she chooses to teach. It doesn't help that the father of the family Mary is boarding with is one of her biggest followers. When Miss Peale witnesses a boy trying to steal a kiss from Mary (who responds with a slap), she labels Mary a "Jezebel" and drives Mary out of town. Once back in Walnut Grove, she sobs through the details of her experiences. Pa encourages her to go back to the town and confront Miss Peale, which she does in a "showdown" during a church service. Though she spouts hellfire and brimstone, Mary proves that Miss Peale can't even read the bible she so often (mis)quotes from. The boy who stole the kiss confesses to his actions, and the townsfolk see the light. Miss Peale is forgiven by Mary in a final, touching scene.
This episode is a departure from the usual LHOTP. It includes mostly characters never seen before or after appearing here. Laura does not even surface. Mary, however, really comes out of her shell and her maturity is evident as she skillfully teaches the class, and later lets Miss Peale have it. Not "one of the best", but worth viewing.