In a world where dead people turn into books and are stored in the Bantorra Library where anyone who reads a book can learn their past, Bantorra Library is maintained by Armed Librarians who wield psychic powers and their enemy is a religious society known as Sindeki Kyoudan.

Episode 0, consisting of two subepisodes: "Sekirei Shindan" (鶺鴒診断) and "Sekirei Yoka" (鶺鴒余暇), of Sekirei: Pure Engagement included on the first DVD/BD volume.

The cheerful Yuuki Cross and the gruff Zero Kiryuu are members of the disciplinary committee at Cross Academy, which houses two very distinct classes: the Day Class and the Night Class. Their job consists of upholding order between the classes when they switch out. While that may not seem like an especially difficult task, the Day Class is unaware of the truth behind the Night Class—their utterly gorgeous students are vampires. Ten years ago, Yuuki was saved from a vampire attack by Kaname Kuran, a Pureblood vampire. Now, Kaname is the leader of the Night Class, and Yuuki's disciplinary committee position allows her to see him again, making her feelings for him grow complicated. Meanwhile, Zero bears a white-hot hatred of all vampires and believes they can never live in harmony with humans. But a secret from Zero's past soon threatens the fragile peace of all at the academy, and things may never be the same again. [Written by MAL Rewrite]

After being brutally murdered along with her family, Makina Hoshimura turns into a Shikabane Hime, a living corpse contracted to the Kougon Cult, in order to exert revenge on the mysterious undead organization responsible for her death. She is assisted in this task by Keisei Tagami, her contracted priest and former friend. This series follows the story of Keisei's younger brother Ouri, a boy with an unusual attraction to death, who slowly discovers his brother's secret and gets dragged into the world of the Shikabanes.