The Tyranny Of Queen Daybreaker

Something has caused Celestia to turn into the tyrannical Daybreaker, and now, only one little filly can stop her, but she must learn from the past, in order to save the future

Power has corrupted Celestia, and now, one little filly must lead the rebellion to vanquish this evil, with help from the most unexpected source, and a past she never knew of.

(Inspired by the Assassin's Creed 3 game DLC Tyranny of King Washington.)