The anime's setting is a fictional Japanese city named Sugomori City. One day, Noriko Sonosaki tells her classmate Katsuhira Agata, "You have been selected to be a Kiznaiver." The Kizuna System, which allows Katsuhira to share his wounds, connects him to the classmates whose lives and personalities completely differ from his. The Kizuna System is an incomplete system for the implementation of world peace that connects people through wounds. All those who are connected to this system are called Kiznaivers. When one Kiznaiver is wounded, the system divides and transmits the wound among the other Kiznaivers. Sugomori City is built on reclaimed land, but as the years go by, the city's population is decreasing. The story is set in this town where Katsuhira and the others live.

The year is 1931. Prince Tokugawa Yoshinobu holds absolute control over Japan. Remnants of the Meiji era’s culture can be seen around the city, but scientific technology and Japanese esoteric cosmology Onmyodo are also developing. Yet lurking behind the glitz is Kuchinawa, a dissident group planning the assassination of the prince. Tasked to extinguish these dissidents is Nue, the government’s secret executioner group. Sawa Yukimura, who works for this organization, suffered at the hands of the Kuchinawa boss. Her entire family was murdered and she dedicated her life to avenging their death.

In the near future, Vivy, a diva-type A.I., went up on stage each day with hopes of putting her heart into her song. One day, the A.I. Matsumoto, who claims to have arrived from 100 years in the future, appears before Vivy with an important request...

Music is the light that illuminates people's hearts-- and that "light" was suddenly taken from the world. The world changed the night the black "Kuroya Meteorite" fell. Grotesque monsters known as D2 emerged from the meteorite and began to overrun the land and people. As the D2 were drawn to melodies people played, eventually "music" itself became taboo. However, those who opposed the monsters appeared. They the "Musicart," girls who draw power from music. They possess the great operas and musical scores of humanity history and use them to defeat the D2.

It’s 1923, and the mysterious blood source Ascra has unleashed a horde of vampires across Japan. In response, the government spawns Code Zero. With S-rank vampire Defrott and the rookie Kurusu, this kill squad is made for one reason: to hunt the undead!

Imperial Capital, 1930. A strange group of people carrying musical instrument cases landed on Tokyo station. They are called the "Jaegers", who came to hunt vampires. Amongst them, there stood a young man with striking serenity and unusual aura. His name is Yuliy, a werewolf whose home village was destroyed by vampires. Yuliy and the Jaegers engage in deadly battle over a mysterious holy arc only known as "The Arc of Sirius". What truth awaits them at the end...?

Fena Houtman remembers little about her childhood. Orphaned and raised as a servant in a brothel, her life changes when she escapes to an island of pirates where she discovers the truth behind her family. With Fena being the only one able to unlock her family’s secrets, and a formidable crew of female pirates on her tail, she must take her place as captain of her Samurai crew for a high seas adventure!