Twilight Sparkle is called away to tend to Luna when she falls ill. As Luna grows sicker and Twilight more determined to help the younger princess, she begins to uncover dark secrets about the elements, the alicorns, and her own past.
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.
Twilight fights against sinister manipulations, struggling to overcome a deep-seated darkness within. As she battles to preserve everything she cares about, she will sacrifice anything necessary to succeed. But the price of victory may be herself.