A routine rescue from a no-name villain goes wildly awry as Celestia is flung into the lethal, living nightmare that is Tartarus. No great problem for an immortal, but to Celestia's absolute horror, Twilight has followed her in.
When the Goddess spoke to her, Celestia learned she was going to die. She also learned her true date of birth. Eleven years ago, seconds after a young filly named Rainbow Dash completed her first Sonic Rainboom.
Twilight has been chosen as this year's addition to queen Nightmare Moon's mysterious cadre of personal students. She gets to live in a castle, receive lessons from their sovereign, yet her parents remain sad for some reason.
To save Rarity, Twilight and her friends must follow her to a war-torn world struggling to survive an eternal winter night, where Hearth's Warming never happened.
Everypony deserves a chance and nopony upholds that principle better than Equestria’s leaders, the Royal Princesses. This is not without risk and compassion can trump judgement, so what would be the cost when they find their trust has been misplaced?
Princess Celestia decides to teach young Twilight a lesson by reading to her a bedtime story from a banned book. To this day she wonders whether it's had an adverse effect on her protege turned Amazon.
Darkness. Not the ordinary sort that is concomitant with night-time. This Darkness is alive, filled with terrifying purpose, and it is stalking Princess Celestia through her castle.
The last time Luna and Celestia met there was an argument. That would be the last memory that either would carry of the other as they faced separate futures that would never cross again. If only it had been different.