Spica Virgo is a budding witch who admires Claude Sirius, a skilled wizard and teacher who mysteriously vanished one day. However, due to her clumsiness and lack of skills, she feels it is difficult to fulfill her dream of entering Royal Diana Academy, a prestigious magic school where Claude was once a teacher. One day, she encounters a black cat. She is surprised that the cat can talk and asks it for help in entering the academy. After learning that the cat was formerly human but was cursed to have this form, Spica aims to undo the curse. She learns that she has "Rebirth Magic", which gives her the power of regeneration, and that she can undo the curse by kissing the cat's butt. She does so reluctantly, leading the cat to reveal itself to be Claude. With this, Spica enters the academy, with Claude becoming her teacher, with Claude still maintaining a cat form as Spica's magic remains too weak to lift the curse fully.