The year is 2027, and the city of Kyoto has undergone tremendous technological advancement. Within the city live two classmates: Naomi Katagaki, a socially awkward and introverted boy; and Ruri Ichigyou, a girl with a cold personality who is often blunt with people. Despite sharing Ruri's love of reading, Naomi is afraid to approach her due to her unfriendly nature. One day, while out on a walk, Naomi witnesses a crimson aurora pierce through the sky for a brief moment before vanishing. Shortly after, he encounters a three-legged crow and a mysterious hooded man, who reveals himself to be Naomi from 10 years in the future, explaining that he has come to change an imminent tragic event that happens to Ruri soon after they start dating. Initially taking his words with a grain of salt, present-day Naomi follows his future self's instructions and starts getting closer to Ruri, determined to save her. Will he be able to change the future?

Vampires walk among society, existing as part of its underbelly. They do not require blood to survive, but extreme emotions can immensely increase their bloodlust, turning them into uncontrollable monsters. Tsukasa Taira, a 22-year-old university student, learns of the existence of vampires when her longtime friend reveals himself to be one of them after a tense confrontation with Yuuki Anzai—a human and vampire hybrid. Her friend is arrested, and Tsukasa soon finds herself drawn to Anzai, who reluctantly reciprocates her feelings. However, this unconventional romance may prove too difficult to maintain, as Anzai struggles to contain the part of him that wishes to devour Tsukasa.

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.

Show them your A-O face! As an innocent child, Ao Horie would unhesitantly proclaim the origins of her name. Now that she is in high school, she is determined to study hard in order to one day escape the influence of her lascivious father, a famous erotic author. However, when the amiable Takumi Kijima confesses to Horie, her mind runs wild with scandalous thoughts. Moans eager to escape, legs crossing, and a warmth spreading through her body, Horie cannot help but misconstrue Kijima's rather pure motivations. To make things worse, no matter how hard she tries to ward off Kijima, his advances do not stop. Now, if only she could just study!