Kinki: Zettai ni Yatte wa Ikenai 13 no Koto
Mourning Demon·禁忌 絶対にやってはいけない13のこと
Akio returns to his hometown and is haunted by memories of Yuka, a childhood friend who vanished a decade ago during a game with friends. While Akio recalls the event with vivid, terrifying details involving monstrous beings, his friends have no memory of what occurred. He dismisses his recollections as nightmares until one of his friends disappears without explanation. This confirms his worst fears—something is still present, lurking in the shadows. The question remains: who, or what, is observing them?