Rainbow Dash receives an Urgent Message calling her to Cloudsdale when she's hanging out with her friends. Once there, the revelations thrust upon her will change her view of the world for the rest of her life.
A nod to one of my favorite fan theories. Albeit a largely debunked one.
[embed]youtube.com/watch?v=ms9-hY3s0iM[/embed]
What is this fan-theory?
10383809
Just that.
Ok then