Plot
Long ago, in ancient times, there existed a flower which possessed an evil will. This flower gave birth to six beings called Intoners, beautiful women with the ability to manipulate the magic of song. One of them, Zero, fought the other five, One, Two, Three, Four and Five, as she deemed them to be a threat to the world. In the aftermath of the conflict, the Intoners were sealed in another dimension by Zero's dragon partner, Mikhail. The flower was also destroyed hence protecting the world from the threat of it.
However, the peace only lasted for some time.
In modern day Japan, the seal containing the Intoners was discovered by archeologists. As the archeologists examined it, the seal was accidentally broken causing the six Intoners to be sent to different parts of Japan as well as a seventh Intoner, Six to emerge out of it. Six who represents the flower's evil will began to summon monsters to kill the archeologists. After killing them, Six went into hiding somewhere in Japan to devise a nefarious plan.
Meanwhile, six ordinary individuals, Arisu Kujou, Shirou Ichigami, Nichijou Yamato, Sano Eijima, Kyouji Kusakabe and Gorou Tatsumi, found each of the Intoners and became acquainted with them. Through a series of circumstances, the Intoners discover that they are able to share part of their powers with their new companions enabling the latter to wield mystical weapons called Dragon Hearts. Also, the Intoners realize that their song magic have been stolen by Six and fear that she could be using them for something evil. Soon, the Intoners and their companions embark on a journey around Japan to find and unite with each other to fight Six.
In their journey, they have to constantly fight monsters sent out by Six to attack innocent people. In addition, they have to fight Six's accomplices, who are tasked to impede the heroes' journey. Furthermore, the heroes will meet two old allies of the Intoners as well as learn about Six's plans and the reason for Arisu, Shirou, Nichijou, Sano, Kyouji and Gorou being able to wield the Dragon Hearts…