In humanity's distant future, two interstellar states - the monarchic Galactic Empire and the democratic Free Planets Alliance - are embroiled in a never-ending war. The story focuses on the exploits of rivals Reinhard von Müsel and Yang Wen Li as they rise to power and fame in the Galactic Empire and the Free Planets Alliance.
While hanging out on the roof of her school, Nao Ueshima discovers a flock of flying cats. In her haste to snap a picture, Nao tumbles over the side of the building. But instead of plummeting to her doom, Nao is guided by an unseen force that allows her to land safely on her feet. Determined to unlock the secrets of the flying cats and the identity of her rescuer, Nao soon learns that not only is one of her teachers able to control the wind, but he can also teach others to control it, too!
After hearing the rumor about a mysterious virtual reality headset which allows the wearer to participate in Versus Road game from his friend Hoshiai, Kuon finds himself acquired one of said headsets and enters the game along with 99 chosen players. There, the ring mistress of the game, Shuka, presents a golden suit of armor as the game's grand prize and explains that the first level's goal is to survive by any means necessary as their numbers are getting halved. To increase the challenge, two biomechanical demon beasts, Horrors, are released upon the players where the demons will devour those who failed to escape their grasp.
Rei Suzumura, Zero the Silver Fanged Knight, is patrolling on his own when he encounters the white Horror Ring, who has created a commune where Horrors and humans live together in harmony, so long as one human a month allows themselves to be devoured by the Horrors. Rei, along with Makai Priest Cain and the knight-in-training Yuna are ordered by the Makai Senate to slay Ring and free the humans under his thrall by means of Yuna's mother the Makai Priestess Iyu.