The serial killer, reincarnated as a young girl, mercilessly hunts down Narr.

Nanaka, a woman in her late twenties who runs a business as an exorcist—essentially a "jack-of-all-trades"—is asked to check on a distant relative one day. There, she encounters a strange girl named Riru. The requests she receives are rarely related to actual paranormal incidents; instead, she often finds herself in situations involving unsettling human horrors. As she listens to the clients' stories and tries to unravel the mysteries of the cases, she discovers that Riru, whom she has taken on as an assistant, possesses a unique talent that leads her to solve one dark and sinister crime after another. Riru's calm demeanor and way of thinking are far beyond what one would expect from a 10-year-old girl, and above all, her judgment seems to reveal a deep understanding of the mindset of criminals... It turns out that within her lies the reincarnation of a serial killer who met his end with the death penalty.