Finally, the day of Mai's high school graduation has arrived. While Sakuta eagerly waits for his girlfriend, an elementary schooler who looks exactly like her appears before him. Suspicious, and for all the wrong reasons... Meanwhile, Sakuta and Kaede's father suddenly calls, saying that their mother wants to see her daughter. She was hospitalized because Kaede's condition had been too much for her to bear, so what could she possibly want now?

What will it take to make her wish come true? After a draining December, Sakuta is quickly nearing the end of his second year of high school. Since Mai is a third-year student, they don't have much time left together before graduation rolls around. Meanwhile, his sister, Kaede, is slowly but steadily venturing outdoors again. Just as she begins to find her footing, she announces her most ambitious goal yet—attending her brother's high school! Sakuta knows better than anyone how difficult this will be for Kaede, and he's ready to support her however he can. He's just not sure if that's what's best for her...or what she really wants...

Following the events of Satsujin Kousatsu (Zen), Shiki Ryougi has been in a coma for two years due to a traffic accident. When she finally awakens, she has no memories of her past and is plagued by a profound loneliness. Even stranger, she notices dark lines encompassing the things around her, and if she touches them she can disassemble the object—something which completely terrifies her. Her friend, Mikiya Kokutou, enlists the help of Touko Aozaki, a mage who can help Shiki understand what her eyes—the "Mystic Eyes of Death Perception"—are truly capable of and how to use them properly. 

The Nocturnal Community Relations Division is a team of people who specialize in solving cases involving the ominous occult creatures of the night unseen by ordinary humans. Young and unsuspecting Arata Miyako has been assigned to the Shinjuku Ward Office of the division, where he meets his fellow members Theo Himezuka and Kyouichi Sakaki. On his first night, Arata finds himself on a mission where he discovers to his surprise that not only does every supernatural creature he once thought to be fictional actually exist, but also that he is the only human who can understand their non-human speech. Arata's surprises do not end there, as later that night, he meets a legendary creature called a Tengu that refers to him as the famous Heian-era exorcist, Abe no Seimei. Unfamiliar with the exorcist, Arata pays no mind and continues to work with his team, utilizing his unique ability to assist in the resolution of their cases. Mistaken by many occult creatures as Abe no Seimei and quickly becoming notorious for his special ability during his work, Arata becomes curious of his origins and invests himself more into solving cases regarding occult creatures he encounters once he learns of a certain connection between himself and the exorcist. However, Arata will quickly find that dealing with supernatural creatures is not as simple as he thought, as danger begins to play a fundamental role in his everyday findings and his ability starts to present an unexpected issue.