Monica Everett, the Silent Witch is visited by a colleague to go undercover at Serendia Academy.

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

Monica is accused of being an accomplice for attacking Felix, so she looks for the culprit to clear her name.

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.

It's the weekend and Monica is freed from her duty, so she decides to go to the city of Craeme with Nero.

Serendia Academy is a distinguished academy dedicated to nurturing refined ladies and gentlemen, so girls are required to take ballroom dancing and tea party classes. Since Monica lived in isolation in a mountain cabin for a long time, she must re-take her ballroom dance test. Monica was already struggling, and to make matters worse, the tea party announcement was made. Her group is Monica’s friends Lana Colette and Casey Grove, as well as Claudia who is an intelligent woman known as the “walking library.” How will the tea party and Monica’s re-examination for the ballroom dance go?