An ordinary high school girl named Airi Katagiri, who has a personality that cannot ignore people in trouble, is suddenly transported to the demon world when a magical circle appears at her feet while on her way to school. The demons of this world had been performing a ritual to resurrect their Demon King, and Airi was accidentally summoned as a result. Although the demons initially believe their ritual failed upon seeing her arrive, they soon discover that Airi possesses the power of the Demon King. With no clear way to return to her original world, Airi decides to become the Demon King herself while searching for clues that might lead her back home.

The story follows Airi as she navigates her unexpected role in the demon world, a realm where demons have been attempting to revive their ruler. As she embraces her new position, she gradually gains the acceptance of the demons around her, who initially doubted her capabilities. The series combines fantasy and isekai elements, following a high school protagonist who rises to a position of great power in a supernatural realm. The narrative focuses on Airis journey as the "JK Demon King" descending upon the demon world, exploring themes of adaptation and unexpected leadership. Over the course of the complete story, which spans 26 chapters collected across three volumes, Airi encounters various challenges in her quest to understand her powers, earn the trust of her demon subjects, and potentially find a way back to her normal life as a student.