Demon Queen Abyss is deeply troubled. As the ruler of the demon realm, her sworn enemy is the Hero, a young and inexperienced boy who should be easy to defeat. However, a critical complication arises: the Hero has no idea who Abyss truly is. Instead of seeing her as a mortal foe, he earnestly regards her as his beloved master and grows deeply attached to her. This leaves Abyss stuck in a comedic dilemma, unable to carry out her demonic duty of defeating the Hero because of the genuine affection he shows her. The story follows her daily struggles to reconcile her role as a demon queen with the increasingly warm and absurd relationship that develops between them, blending fantasy, slice-of-life comedy, and ecchi elements.