Princess Celestia died.

This, of course, started the biggest investigation in Equus history. No pony was certain as to how she died, whether it was of foreign plague or assassination, no pony could determine the causing factor. This caused panic, naturally, but the citizens of Equestria quickly realized that they had an even bigger problem on their hooves.

The sun had died with Princess Celestia, and all that remained, was darkness.

It is now up to Twilight and her friends to restore civil order within Equestria. This may not be easy though, as an insidious evil now lurks within the endless black.