In Victorian-era London, on the night of Ciel Phantomhive's tenth birthday a fire destroyed his manor and killed both of his parents. In a moment of death Ceil strikes a deal with a demon, his soul in exchange for revenge. This demon becomes his butler and calls himself by name of Sebastian Michaelis, to protect and serve Ciel until the deal has been completed. One month after the fire Ciel returns from being missing, with his new butler Sebastian. Ceil is now the head of the Phantomhive corporation, handling all business affairs as well as the work as the Queen of England’s guard dog and looking for his parents murders.
Eleven years after the introduction of internet-connected, augmented reality eyeglasses and visors, Yoko Okonogi moves with her family to Daikoku City, the technological center of the emerging half-virtual world. Yoko joins her grandmother's "investigation agency" comprised of children equipped with virtual tools and powerful metatags. She quickly crosses paths with Yoko Amasawa, an expert hacker of the virtual environment, as Amasawa relentlessly seeks to "unlock" the mystery of a computer virus that emerges from an inaccessible corrupted space.
Zero is a witch who is ignorant of the world and travels with a half-beast half-human mercenary who longs to be human. Witches who practice sorcery exist in the world, however, in this era no one knows how about the art and study of witchcraft. Zero is going on a journey to search for a magical tome called "The Book of Zero" that hides a power that can destroy the world. The mercenary travels with her as her guard.
Tokiha Mai and her sickly younger brother, Takumi, have received a scholarship to attend the prestigious Fuuka Academy. On the way, the ferry they are travelling on becomes the site of a destructive battle between two girls wielding apparently supernatural powers. This is only the beginning of their troubles, as Mai learns that she herself possesses these powers - the powers of a HiME.
In 2018, humans and wizards live together in Tokyo. Police continue to protect order in society, but wizards are tried according to magical law, in special courts defended by wizard barristers. At age seventeen, Cecile has just become the youngest wizard barrister, and begins work at the Butterfly Law Offices. While she hasn't realized it yet, she has tremendous magical potential.
Enter Sentan, a lush, tranquil island encased in war between the military and those with Hiruko, known as X'amd. On one of these warlike days, Akiyuki Takehara heads off to school and gets caught in a raid by the creatures. Through a series of events he is transformed into a X'amd, and with the help of a Tessikan woman Nakiami along with his highschool friend Haru, Akiyuki is forced to learn to live with the Hiruko or faces the danger of losing his self-control and turn to stone.