Princess Celestia has a special task for Twilight Sparkle. The seal that has kept the forces of Tartarus at bay for thousands of years is now at its breaking point, and Twilight must discover an artifact known as the Element of Wisdom in order to reinforce the seal. Unfortunately, the Element of Wisdom has been corrupted into its current form, the Alicorn Amulet, and the only one who had known how to use and purify the Element of Wisdom was Starswirl the Bearded...

As Twilight seeks out this legendary unicorn mage from thousands of years in the past, she instead finds herself on an adventure that she never anticipated...

(Credit of picture goes to egophiliac)