Sumireko stumbles into supernatural incidents the way other people stumble into puddles, except the puddles are cursed and the consequences stick. The chemistry between her and Ren works because she's chasing the story and he's trying to survive it, two people investigating the same mysteries from completely different angles. The show builds real dread through Japanese folklore that doesn't need jump scares to unsettling, just the slow realization that some urban legends exist because something terrible actually happened. Pacing stutters in places, and the fanservice occasionally derails the atmosphere it spent scenes building. It still works because the mysteries themselves are written to reward paying attention, and by the end you understand why Ren looks at Sumireko the way he does.

Sumireko Ogawa is a 28-year-old former literary prodigy who now clerks at a bookstore, her hopes of publishing stalled by unfriendly editors. Rumors of strange incidents around the city revive her ambition. After reading verses from an odd book turns her into a child, her coworker Ren Adashino, who knows the occult well, warns that the change will kill her unless she reads more of it. Restored to adulthood, she joins Ren and his sister Oto in probing urban legends, black magic and ghost stories. Sumireko has a talent for setting off supernatural events, while Ren keeps secrets and aims of his own. The mix is horror, mystery and the supernatural, with ecchi elements.