Monica transfers to Serendia Academy after accepting the top-secret mission. Her mission is to secretly guard the second prince Felix without him noticing. 

Louis's familiar Ryn was at the Serendia Academy to drop off his message when they detected an irregular mana by the boy's dorm. When they went to the woods behind the dorm, they found Cyril losing control of his mana and slowly spreading ice around and freezing himself, too. Monica identifies the reason behind the mana rampage and finds out that there's a culprit behind it. The hidden secret of the student council gets unveiled.