It has been a few nights since the events of A Nightmare's Nightmare. Cale McManus, human assassin still carries the scars from his fight and is now the love interest to the Princess of the Night, as well as Nightmare Moon. But what happens when another mare of darkness comes to Equestria and has her eyes fixed on the mare that loves the human?

Note: If you haven't read the following, do so before reading this.

The Four Horsemen of Equestria (First)
A Nightmare's Nightmare (Second)