In the Reiwa era, even magic schools have seen the decline of delinquency. The Black Magic Dorm, once a rowdy haven for troublemakers, now stands nearly empty and on the verge of being shut down. The environment is harsh, teachers despise it, and graduates struggle to find jobs. Into this dying dormitory move three new students: Kizuna, Aiko, and Kokoro. All three are thoroughly self-centered and ruthless. Upon seeing the dorm’s miserable conditions, each privately vows to escape as quickly as possible, caring nothing for the fate of the other two. They scheme, backstab, and indulge in petty power trips, making life miserable for one another in a chaotic slapstick comedy.

Unknown to them, a dreadful prophecy hangs over their heads: one of the three will become a demon king and bring destruction to the magical world. As the girls fight among themselves, the prophecy gradually draws the attention of the magical establishment. The gentle vice principal suddenly turns hostile, and the girls are captured, surrounded by dragons and angels, and told they must die for the sake of the magical world. The three realize that if only one of them is fated to become the demon king, the other two might survive—if they can eliminate the right target.

The story follows their increasingly absurd and selfish attempts to escape the dorm and avoid the prophecy, while external threats escalate. The highest magical authority, the Twelve Zodiac Council, sends an assassin named Shirasuna Sutan, whose predictable but unavoidable poison attacks target the trio. One of the girls apparently dies. The council’s leader eventually confronts them with an unexpected argument, pushing events toward a climax that will decide the fate of the world. Throughout, the cast remains uniformly selfish and untrustworthy, with no one rising above their petty nature—a comedy that never lets up on the “trash girl” premise, even as the stakes become world-ending.