For past year or so, Equestria has looking for threats on the outside of Equestria. However, somepony on the inside is going to manage to make Celestia and all of Equestria kneel before the sheer terror of them. The era of the four princesses is at end, will anypony see it coming?
Quick Notes

• Anything beyond Season 5 is non-cannon to this story
• Please Leave Constructive Criticism
• This is a crossover with Doctor Who