In Canterlot Castle, a single protector guards over the Princesses of Day and Night. The Royal Guardian, a single unicorn chosen by Empress Faust herself to protect the Princesses at all times. But during an expedition to the northern border, a changeling attack kicks off the fires of war...and unearths a long lost royal....

For 1000 years, the Princess of Night has been locked up inside the moon, The only evidence that she even exists is the pony shaped emblem in the moon. On the longest day of the 1000th year, Nightmare Moon is released from her prison, and 1000 years of pent up rage is unleashed upon Equestria. it's up to the mane 6, joined by a pony out for revenge, to stop Nightmare Moon and her quest for destruction