At Midgar Academy, an all-girl school exclusive to a group of girls known as D's, Yuu Mononobe stood out as an extraordinary student. The girls possessed a rare ability to generate dark matter, transforming it into powerful weapons. What set Yuu apart was the fact that he was the only male D known to exist, making his acceptance into Midgar a significant event. However, Midgar was not just any ordinary school for the D's. They emerged as a result of the sudden appearance and disappearance of monstrous creatures known as "Dragons," who wreaked havoc across the planet. Soon after, girls with symbols on their bodies and uncanny powers similar to those of the Dragons began to be born. The D's attended Midgar to learn how to control and amplify their unique abilities in the fight against the Dragons. Yuu had to navigate his way through his classmates and ally himself with them to investigate and eliminate the powerful Dragons that posed a threat, including his sister, who also attended Midgar.