The episode ("The Hidden Boss Is Summoned to the Castle") begins with Yumiella Dolkness arriving at the royal castle after creating a black hole above the academy. There, she is granted an audience with the king, who apologizes for his son's and the teachers' unfriendly behavior toward her. The king is curious about Yumiella's alleged Level 99 status and arranges a test by Knight Captain Adolf, the kingdom's strongest knight.

In an impressive display, Yumiella effortlessly dodges Adolf's attacks, which impresses the king and confirms her extraordinary abilities. The king then demands to see her magic, leading to a demonstration of her dark magic. This sparks a discussion about the nature of dark magic, with the palace's head mage explaining that it is neither good nor evil, like any other magical attribute.

The king praises Yumiella for her deeds and offers her any reward she desires, including a royal title or even marriage into the royal family. Yumiella politely declines, as she wishes to live a peaceful life. The king assures her that he will ensure her peace and safety.

Later, Yumiella has a private encounter with the queen, who reveals another shocking truth: the return of the Demon Lord is imminent and expected within two years. The queen asks Yumiella for help in defeating the Demon Lord and explains how important it is for the royal family to emerge victorious to maintain their legitimacy. The queen also speaks about the political factions within the kingdom and warns Yumiella about the anti-king faction, led by Duke Hillrose, advising her not to get involved with them.

Back at the academy, Yumiella notices a significant change in how her fellow students treat her. Students who once avoided her now engage her in conversation. However, she is also confronted with numerous marriage proposals, particularly from members of the anti-king faction, who seek to use her power for their own purposes.

The episode culminates in an encounter between Yumiella and Eleonora Hillrose, the daughter of Duke Hillrose and a prominent figure in the anti-king faction. Eleonora, known for her tyrannical behavior, invites Yumiella to join her group, but Yumiella tactfully declines. Eleonora then demands that Yumiella stay away from Prince Edwin, mistakenly believing she intends to marry him. Yumiella clarifies that she has no such intentions and redirects Eleonora's attention back to herself as a suitable partner for the prince.