Twilight Sparkle is startled to find that the most important history books in Equestria are going missing. Will she and her friends be able to uncover the identity of the mysterious new villain responsible? Meanwhile, Pinkie Pie and Rainbow Dash uncover a plot to attack Yakyakistan! That's before Pinkie gets trapped in Discord's chaotic dimension, or when Fluttershy and Twilight Sparkle follow Mage Meadowbrook's notes to find a miracle cure for any ailment in Equestria! Plus, the Cutie Mark Crusaders have a new challenge when a young pony doesn't want to follow in her family's hoofsteps. Collects issues #51-65 of the My Little Pony: Friendship is Magic series.