Where was Luna during the attack on Canterlot? Why did she not aid her sister in protecting the city? Perhaps she was protecting other ponies... or perhaps something more sinister occurred.
Lunar Limbo is a cold place, made even colder with a being whose only purpose is to augment one’s negative emotions and one’s desires, who insists that Luna was right to try to take over.
A tiny filly stands on an open plain. Somewhere in the distance a fleeting glimpse of white leads her on, her heart yearning towards it. A dark power with her face attempts to stop her. And nothing here is quite what it seems...
When the sun stays in the sky for three days straight, everybody turns to the princesses for guidance. Unfortunately, Luna is nowhere to be found, and Celestia seems to have something else on her mind.