After the Great Human-Demon War comes to a close, humans use a magical device known as the Gear to found the Hero Institute, a school for raising a new kind of hero. Ruchika, a wild and reckless demon girl, travels to the city in the hopes of joining the institute. There she meets Leonie, the serious-minded daughter of the Almighty Hero who defeated the Demon Lord. Taking a liking to her immediately, Ruchika proposes-right in the middle of their entrance exam! Do these two girls have what it takes to become heroes? And can love bloom between a human and a demon?