Trouble is brewing in the Unicorn kingdom as the royal castle is suddenly cut off from the outside world. Mysterious disappearances continue until an entire town is found deserted, and an attempted investigation is cut short by nightmarish monsters. Not about to let themselves be cornered, the unicorns prepare for battle. An apprentice wizard, Star Swirl, and his friends are among those called upon to defend the crown, but nopony is truly prepared for what they are about to face.