Twilight's been noticing some changes, but she isn't the one changing. Everything else is changing while she stays still, immobilised in time while the world moves on without her, and she has been thinking recently about the point to life. Namely that, for her, there isn't one.

Princess Celestia has gazed into the fiery pits of Tartarus itself, gone hoof-to-hoof with gods and demons. She is the embodiment of light, slayer of all shadows, and fears nothing.

So what happens when she finds something she does, indeed, fear?

When Sweetie can't sleep, Rarity decides to tell her a story. A story about how Celestia and Luna made the ponies of Equestria, and how they came to rule as sisters side by side.

Wrote it on a whim. 12 periods. 999 of the letter 'e', 611 of the letters 'a' and 'o', respectively. I'm quite proud of it, actually.