In this prequel to the "X" TV series, a beautiful, young, bedridden dreamgazer named Kakyou remembers the life and death of a remarkable young woman whom he met in dreams. He also recounts his dreams of a tragic future in which the fate of the Earth will be decided.

His destiny has finally arrived as the young Shirou Kamui returns to Tokyo after 6 years. A powerful psychic, Kamui vows to protect the happiness of his childhood friends Fuuma and Kotori, even if it means avoiding them. But fate is cruel, whether or not Kamui wants to be involved; he holds the future of the world in his hands, given the choice of becoming a Dragon of Heaven or a Dragon of Earth. The Seven Seals gather, and so do the Seven Angels; all individuals who have their destiny carved out as one who would battle for the fate of the world. What future will Kamui choose to become reality?

In a shocking turn of events, humanity has won its first battle in the Ragnarök tournament—a series of 13 fights that will decide the fate of mankind. Zeus, the head of gods, sends the demigod Heracles for the next round to avenge the humiliated Greek pantheon. To face this hero loved by gods and humans alike, the Valkyrie Brunhilde decides to use Heracles' complete moral opposite: the infamous serial killer Jack the Ripper—leaving human beings unsure who they should support. Meanwhile, tensions begin to rise between various divine pantheons, and rumors of a traitor jeopardize the unity of those who want to annihilate humanity. As the line between friend and foe becomes blurred, Brunhilde will do everything she can to make her machinations successful.

Far to the north of the world lies Hell's Gate, a portal formerly used by the Demon Lord to invade the human realm. Thanks to the legendary hero Shion Bladearts, wielder of Excalibur, and his loyal band of companions, the Gate was sealed off and the demonic threat was vanquished. Unfortunately, the seal was incomplete and has begun to weaken, allowing the demons to once again begin their attack. Worried about the safety of his village, selfish and perverted farmer Touka Scott dig pitfalls to defend against the demons. But fear not, for Shion is on his way to reseal Hell's Gate and save humanity! Or at least he was, because the legendary hero is dead, having fallen into one of the pitfalls Touka dug. Luckily, dealing with the dead is the specialty of necromancer Anri Haynesworth. While she can't revive him, Anri can at least salvage their quest by forcing Touka's soul into Shion's rotting body and dragging him along to Hell's Gate in Shion's place. Not wanting to be left behind, Touka's childhood friend Yuna Yunis tags along. Together, the three of them set out as what just might be the most unsuitable party to ever try to save the world!