The Rising Night
A long time ago, in a land far away, two sisters lived in exile. Hunted by the unicorns, banished by the pegasi, they lived in a wood only by the grudging generosity of the earth ponies.
Some time ago, in a land not too far from here, a strange little pegasus appeared from the aether, seemingly bringing trouble in their wake.
Not too long ago in the grand scheme of things, in a land much too close for comfort, night fell in the village in the woods and swallowed it up whole. It fell to the two most powerful mares in the realm to defeat the great evil, but after they had been wronged so many times themselves, would they lift a hoof to help?
A long time ago. Far, far away. Never particularly convincing lies when time travel enters the equation.