The Cutie Mark Crusaders become matchmakers when they find out that Miss Cheerilee doesn't have a "very special some-pony" for Hearts and Hooves Day, and see Big Macintosh as the perfect stallion for her. To ensure their plan is a success, they give them a powerful love potion, made from a reciple in an old book. However, after learning the terrible history behind the concoction, they must find a way to break its spell.