Vampires—supernatural beings that feed on the life essence of the unsuspecting at night—have been around for centuries. However, high schooler Karin Maaka is unusual, even among her own kind. Unlike her vampire family, ever since she was a child, Karin has suffered from polycythemia: a rare disorder which causes her to periodically produce excessive amounts of blood. And the more blood she produces, the more anemic and lightheaded she gets, ultimately leading to frequent nosebleeds. Her only solution? Force her excess blood onto random strangers, which surprisingly causes these "victims" to become livelier and happier than before. With her siblings—Anju, her reserved yet affectionate younger sister, and Ren, her womanizing elder brother—helping her abilities remain a secret by altering the affected humans' memories, no one is the wiser. That is, until Karin's newly transferred classmate, Kenta Usui, finds her behavior suspicious. And to make matters even more complicated, Karin feels her blood reacting unusually to Kenta's presence.

Dralc, a vampire who is feared as he is rumored to be invincible. The vampire hunter Ronaldo goes to Dralc's castle after hearing that Dralc has kidnapped a child. But when Ronaldo arrives at the castle, he finds that Dralc keeps dying over every small thing and turning to dust. Dralc's true nature is that of the weakest vampire of them all.

Saenome are tasked with sealing spirits that possess objects and pose a threat to society. Known as tsukumogami, these spirits are generally non-violent, and saenome normally seal them after a simple verbal exchange. Traumatized by a previous deadly encounter with a malevolent spirit, Hyouma Kunato refuses to use peaceful methods and gets into physical confrontations with all tsukumogami that cross paths with him. Deeming this behavior unacceptable for a future clan leader, Hyouma's grandfather, Zouhei, proposes that he starts living with Botan Nagatsuki, a young woman whose family is composed of six tsukumogami—lest he be excommunicated. Determined to track down the spirit that took everything from him, Hyouma reluctantly accepts Zouhei's proposal. As unknown groups of evil spirits begin to jeopardize the balance between worlds, the young man must gain the trust of Botan and overcome his hatred for her mysterious family.

Recap of the first 6 episodes of .