This takes place immediately after chapter 11 of The Adventures of Flare Brimstone and serves as the official, direct sequel.

Far beyond the verge of stars and further still, a portal seldom forms agape. A large rock, a meteor, hurls to the world of Equestria, amidst a star shower. The blistering rock crashes on the plains and caught the attention of Princess Celestia and Princess Luna, who investigates the fallen meteor.

What they uncover will shock them, and when they understand what it is and why will astonish the celestial sisters.