Twilight receives an ancient book of Equestrian myths from Princess Celestia with the warning that all of the myths contain some degree of truth. And she begins to read
Stalliongrad. The city in the frozen north stood for centuries as one of Equestria's oldest settlements. Though largely untouched by the war, it was not without it's secrets. Rainbow Dash is one of those secrets
Luna, upon her return, resumes her pirate activities, much to the dismay of her sister. After raiding the griffon capital, she enters into a maze of treachery and lawlessness unheard of even in her time.