Xie Ying, an ordinary human, is chosen by a black cat to enter a magic academy where all races coexist as the prophesied savior of the world. She moves into the infamous standalone dormitory 001, where her roommates are Sariel, a split-personality Seraph with a dark personality named Saliel; Aivira, a cold and aloof succubus who despises humans yet longs for intimacy; and Siren, an arrogant mermaid who has a psychological trauma involving humans. Each of the three has their own inner demons, and all are destined to destroy the world according to the prophecy. Xie Ying gradually enters their hearts as they make magical cards together and face the academy's trials. A hidden force sets a trap during an exam, creating an illusion that reveals the three roommates' past traumas. Xie Ying joins forces with her roommates to break the trap and avert the prophecy of world destruction.