Roused in the middle of the night, a nightmare clings to the back of Twilight's eyelids. An unlikely visitor has come to the library to let her know that something is wrong with Zecora, and it won't wait until morning. Without even realizing it, Twilight has already begun to collect clues to the mystery that she'll find in the Everfree Forest. Haunted by persistent images from her dreams, Twilight will need more than one mentor's help to unravel a puzzle that stretches from the bottom of Zecora's cauldron to the zenith of Luna's evening sky. The closer they come to an answer, the more menacing the puzzle becomes, until all of Equestria is at risk.

Set prior to Twilight becoming a princess.