Set in the Nightmare Moon Takeover Timeline of the Season 5 Finale.

When Nightmare Moon cast down Princess Celestia and rose to power in Equestria, Rainbow finally found some sense of pride as one of her chosen Night Guard; pegasi empowered by Nightmare Moon herself as her elite soldiers.

When Rainbow joined the Night Guard, she met Applejack, the only pony she felt she could ever truly rely on. The only pony who ever gave her a sense of joy in her otherwise dreary life.

But when Rainbow discovers a terrible secret hidden by her closest of companions, she will find herself with a difficult choice: Choose her pride as one of Nightmare Moon's finest, or the one thing that brought joy to her life.

Written for the Appledash Contest #4, featuring: "A Place Outside of Ponyville", "Deepest Darkest Secrets"