In a world where dragons and magic have become legends, powerful Constellations grant skills to contracted humans and rule through their chosen Players. One man sought only to live quietly, but after the Constellations crossed a line they should never have crossed, he is forced to take action. To fight against the Constellations invading the world, he joins forces with humanity’s greatest enemies, the Seven Princesses of the Demonic Cult. Now, the last Sword Master who protected humanity for centuries must take up his sword once again and fight for the fate of mankind.