Kaito, a court magician who has continued to create barriers to protect the country on behalf of the saint. However, as soon as the Crown Prince's favorite Duke's daughter was appointed as the next saint, he was cursed to use only dark magic when he had no use, and was banished from the country. What's more, the country forced him to deal with the dragon that was mistakenly summoned ... There is no choice but to start living as a pharmacist in the depths of the forest with the dragon.