A tear dripped down the Alicorn's cheek. So this is how it ends.

It's hard to say goodbye, especially when you know you won't ever see them again. It's even harder when you're saying goodbye to your sister, your best friend. Especially when you're immortal. Celestia knows that from experience, having just imprisoned Luna, dear Luna, within the stony, cold satellite that hovers loyally over Equestria. Can things ever be right again?