Thoughts are a substance found universally among humans.
Good thoughts are harmless, but when evil and malicious thoughts build up over time, they can manifest as Thought Beasts that take control of the human body.
Thought Beasts are exceptionally powerful and can wreak havoc on human society. To prevent them from appearing, a small group of people who use the magic within their bodies to fight emerged naturally: magical girls.
It is the duty of magical girls to exorcise and eliminate the Thought Beasts controlling people's bodies, ensuring the safety and stability of human society.
Magical girls, as the name suggests, are "girls" who possess "magic."
A fox-like creature that called itself a cat said, "Well then, young man, let me help you become a qualified magical girl!"
