Celsestia, Luna and Cadence have given their alicorn magic to Twilight so that the evil Tirek cannot have it. But now Tirek has thrown the two goddesses, and Cadence, into Tartarus. How will they escape? How will they stop the evil Tirek? How long will they be stuck down there? Did Luna pack enough toilet paper? Why am I asking you all these question?

Original Fanfic can be found here:
http://www.fimfiction.net/story/197006/a-hell-of-a-time