Ponyville rebuilds after an attack leaves it in ruin, but as ponies vanish during the reconstruction it is clear that all is not well. Realizing that all of Equestria may soon be at risk, Canterlot scrambles to unlock the secrets of what came before.

Following a great tragedy, Rainbow Dash reels from the violent loss of her very identity. And yet, even though the danger has passed, a dark and intangible energy is still haunting her. Is this a crisis of the mind, or is something sinister at work?