Some have quilting clubs. Some have book clubs. Twilight Sparkle decides to have a Cauldron Club. For alchemy enthusiasts. Strangely, she seems unable to grasp that this is a catastrophically bad idea.
When Equestria's Heroes disappear, it falls upon a different group of heroes to save them. A group that... probably wouldn't be Equestria's first choice. Everything rests in Trixie, Lightning Dust, Flim, Flam, and Zecora's hooves.
An untitled book, written by an unknown pegasus, is discovered by Twilight, buried deep in the Canterlot archives. It contains much of the life story of the reclusive Starswirl the Bearded, one of her heroes.