What is necessary is rarely easy or comfortable. It causes anger, depression, and most of all, fear. Pure and simple fear. Fear of what others may think. Fear of what will change. Fear of whether or not things will ever get better.
A follower of Princess Luna is driven by her loss to dare the impossible. She will visit the moon in the Dreaming, and bring back the Princess of the Night.
After the horrible event Luna and Celestia are both thinking about, what had happened. While Luna struggles with the doubt, planted by Nightmare Moon, Celestia has to solve an even greater problem. How to remember a tragedy?
Shunned by the world, filled with her hate and jealousy, Luna had agreed to a horrible deal. As she rises in rebellion against her sister, things turn out for the worst...for her.
Luna is ignored by her subjects and her sister. They shun her night away and her sister behaves like a ruler towards the younger sibling. Luna is sick of it. Her entire life changes, when she meets a certain mare during one destined night.
Luna has been back in Equestria after her banishment for quite a few years, but still feels like she isn't the same pony she was before Nightmare Moon back when she and Celestia were young.
Without the distractions of others, you tend to think. Luna had a long time to think, forced to relive those final moments that turned her into Nightmare Moon. But the thing that haunts her most, to this day, are those final words she said.