Non-canon prequel to The Enchanted Library

As a filly, Rarity's favorite bedtime story was about three princesses trapped throughout Equestria by a wicked spirit of chaos. How she dreamed of finding them all when she was older, especially the princess trapped in a library under a tree. She knew, however, that fairy tales weren't real.

Only when she grew up would she find out how very wrong she was.

Based on an AU a friend came up with in which Rarity stumbles across an enchanted library where Twilight is its spiritual guardian, and both form an unlikely friendship as she helps Twilight be restored to normal.