This story is a sequel to Flames and Twilight.

A dark shadow has fallen upon Canterlot. Darkrai, a being of malevolent evil from another world, has ailed himself with some of Equestria’s greatest foes, and has his sights set on plunging the whole world into an endless, sleepless nightmare.

While Princess Celestia and the Maine Six fight off the invading evil, with the help of a wayward Rapidash, Princess Luna finds herself locked away in her room. Traumatized by the memory of her greatest failure brought upon by the encroaching shadow that played a part in it.
But the princess cannot hide away forever. The nightmare from here past is coming for her for a showdown 1000 years in the making. One way or the other, today the Mare in the Moon will face her fears.

This is a little side-story I conjured up for Flames and Twilight by http://www.fimfiction.net/user/Ausbrony]Ausbrony. It focuses the actions of Luna and those around her between when we last see her in Chapter 6 and when she reappears again near the end of Chapter 8. Since she disappears for this portion of the Fic and I thought I would have some fun exploring the events that might have happened in the meantime.

While reading Flames and Twilight should not be necessary to enjoy this story, familiarity with Ausbrony’s work would help with understanding certain elements of this story (Such as the whole Pokemon crossover thing). Plus it’s a good Fan-Fic in its own right so I recommend it anyway.