The Royal Diana Academy is a prestigious school that accepts individuals with adept magical abilities. Upon graduation, these students find themselves at the top of their field or employed by the royal family. Spica Virgo dreams of studying at the academy, aiming to be a top-rate sorceress like her idol Claude Sirius. Claude is a world-renowned sorcerer who became the institution's youngest instructor, but mysteriously disappeared soon after. Lacking the experience and connections required for admission, Spica finds herself unable to make meaningful progress with her training. One day, however, she meets a talking black cat with magical abilities. Hoping to change the situation for the better, she begs the animal to take her as his apprentice and teach her the magic she needs to attend the academy. The cat accepts the deal on one condition—she must find a way to reverse his feline curse. Despite the arduous challenges ahead of her, Spica is determined to prove herself as a student worthy of the cat's mentorship.

A human may become a vampire only if they fall in love with one—and 14-year-old Kou Yamori wishes for nothing more. Kou has decided to fall in love with a vampire named Nazuna Nanakusa, and he has only 10 months of nightly rendezvous left to realize his goal. Kou's friends, Mahiru Seki and Akira Asai, are slowly coming to terms with the existence of vampires and Kou's decision to become one. As Kou realizes that a woman close to Mahiru is a vampire, he is unsure whether to support this relationship. Meanwhile, Anko Uguisu, the human detective bent on killing vampires, closes in on Nazuna and her coven. When an encounter leaves one of the vampires seriously injured, they learn that their human memories hold the key to a weakness that can be their demise—and to protect Nazuna, Kou must find out about her past.

Panty and Stocking Anarchy, the angel twin sisters, have even more ghosts to exorcize in Daten City, thanks to the failed opening of the Hell Gate. They must continue their ghost hunt alongside their longtime rivals, the sisters Scanty and Kneesocks Demon, who must earn Hell Coins to return to Hell. On top of that, the Demon sisters are staying at the church with Garterbelt, the priest in charge of the Anarchy sisters. These two polar opposite duos will have to set aside their differences if they wish to collect enough Heaven and Hell Coins to complete their mission and return to their respective realms.

In the detective business, everyone knows the name Keiichirou Nagumo. Back in high school, he was called a genius for cracking tough cases that even the police could not solve. But those days are long gone—or so the rumors say. However, one day, an unexpected visitor barges into his office: Mashiro, an energetic high school student who demands to be hired as his new assistant. Although Keiichirou tries to brush her off, Mashiro is persistent. She is determined to become a detective, and to prove her worth, she begins by teaching him about the latest technology and offers a fresh perspective on his business. Thus, Keiichirou takes Mashiro on as his assistant and embarks on a brand new chapter in his career—one where he finds himself constantly surprised by the modern generation of detectives.