Yuu is sent to Midgar and encounters a naked girl at the beach. Iris is deluded into thinking that Yuu is an intruder, so she tries unsuccessfully to attack him, but then loses consciousness and is saved by him. While Yuu talks with Iris, his younger sister who he has not seen in two years, Mitsuki, appears and the two reunite. Afterwards, Yuu, who is enrolled at Midgar Academy and is placed into Class Brynhildr, meets with Haruka, who is the commander of the Midgar forces, and he tells her the reason why he was invited to Midgar, where is a Self-government educational institution whose aim is to collect "D" and to manage them and educate them. In the Brunhild classroom, Yuu shows his classmates the evidence that his is a "D", and they help him to realise that his ability is not a big deal. In the practice room, after Yuu and Iris limber up, Yuu receives a lecture on how to use the power of "D" by the girls. Haruka reveals to Yuu that the "D", who have an "armorial of Dragon", have the potential to transform themselves into a Basilisk, if a Basilisk falls in love with them at first sight. On the way home from school, Iris tells Yuu the reason why she fights, and talks about her childhood and growing up. She tells Yuu that she wants to become good friends with him, but suddenly the sounds of a siren reverberate, and then Iris's "armorial of Dragon" intensifies in response to a Basilisk.
Yuu Mononobe es un extraño muchacho que heredó los poderes de los Dragones, lo que le confieren unas extrañas habilidades. Por cuestiones del trabajo, lo trasladan a Midgar, donde hay una academia para la gente que tiene poderes... el problema es que es el único chico.