Monica, the Silent Witch, has infiltrated Serendia Academy on a top-secret mission to protect the second prince. So far, she's been appointed accountant of the student council and things are going great! ...Or so she thought. With her former mentor arriving at the academy and her over-powered magic under the microscope, Monica is struggling to keep her identity hidden. As if social dances and tea parties weren't terrifying enough. And now, with a new danger closing in on the prince, will Monica reach her breaking point?

Despite the danger uncovered at the chess competition, plans for the school festival and Felix's big debut remain unchanged, making Monica's mission to protect him more important than ever. Then, on the morning of the festival, she learns that someone has snuck a cursed item into the school! Between protecting the prince, confiscating the cursed item, and maintaining her secret identity, Monica has her work cut out for her.