After witnessing his sister's suicide, Kakeru lives the remainder of his childhood in an orphanage, where he meets a young girl named Yuka. Years later, we find Kakeru, now a teenager, attending high school with Yuka. The ordinary days they have come to expect are overturned when they are thrown into an alternate world which they call "Red Night". In it, they are pursued by nightmarish creatures bent on their death. However, as quick as it appeared, the Red Night mysteriously ends. Both are left unsure if their experience was simply their imagination. Later that same day a new student arrives with more knowledge about the experience.
