Sequel to The Celestia Code. When the monsters created by the dark crystal engine escape their prison, it's up to Princess Twilight to deal with them. She gets help and advice from Princess Luna, but things don't go as planned.
Twilight Sparkle had been looking forward to a quiet, relaxing day with a friend, but when Twilight discovers Fluttershy's appetite for blood, the knowledge proves to be anything but relaxing...