Rainbow Dash is trying to adopt Scootaloo, but the filly has a shameful secret. She doesn't know what she is, only that she can't eat like other ponies, and anypony who knew would hate her forever.
They defeated Discord! Rainbow Dash is a hero! So why is everypony acting like she’s a deadbeat? Her friends are all experiencing similar weirdness. Then Rainbow Dash stumbles upon something that shakes her to the core.
When the most unexpected fate befalls Apple Bloom, she thinks her life is over, but what she has found is something far greater than herself, an ancient secret that will shake the world in days to come.