Twilight's long-awaited plans to study the stars are quickly ruined by an impromptu rainstorm. Too far from Golden Oak Library to make it before being soaked, she finds herself sheltering in Carousel Boutique, where Rarity is up late designing her "magnum opus". Insistent on repaying the kindness Rarity has shown her, Twilight attempts to sew alongside her.

Stitch by stitch, it becomes apparent this dress is special indeed, made for a specific event and a specific pony. By the time the final touches are added, Twilight'll know a lot more about her fashionista friend than she bargained for. She just might discover something about herself at the same time.