The anime tells a story from 150 years ago in the town of Planie. A strange disease that turns humans into the undead has spread throughout the land, causing Planie to become known as the cursed city. The priest Kanae lives in a church on the outskirts of town. Ever since he arrived at the town, the number of cases of the disease have decreased. The fate of the town changes when a mysterious man accompanies Kanae. (Source: Anime News Network)

ChroNoiR Episode.0 is a short animation delving into the origins and lore of Nijisanji's biggest Japanese male v-tubers Kanae and Kuzuha, which form the unit ChroNoiR.