Fluttershy had gone off to Cloudsdale for several days. No warning, no 'goodbye, be back soon', nothing. All they know is that she received a letter from who knows who to meet somepony and is off to Cloudsdale. That was almost two week's ago. And since she's gotten back she has kept herself locked in her home, refusing to see or speak with anyone. Why? Her friends don't have the slightest clue. They also don't know that the reason will lead them to more darkness and strife than they know.