With her new apprenticeship under Nightmare Moon, Empress of Equestria and Queen of the Eternal Night, the orphan filly Twilight Sparkle plunges head-first into the conspiracies, secrets and intrigues of the Empire.
A thousand years ago, the three pony tribes failed to form a unified nation, and war doomed the unicorns to near-extinction. Twilight and Applejack now seek the Elements in the hopes of ending the long conflict between pegasi and earth ponies.
At the end of Rick Riordan's The Heroes of Olympus, Book 3: The Mark of Athena, Percy and Annabeth confronted their fate and dropped down to Tartarus to shut the Doors of Death from the inside, but what if they accidentally crossed the line?
Fluttershy and Twilight find two beasts in the forest, and decide to find out what they are, but surprises are in store for them when they realize they are no ordinary creatures...