Shojo Ni Tensei Shita Serial Killer Ha, Mujihi Ni Narr Wo Oitsumeru. 1 (MFC)

[Machine Translation] A suspense mystery in which a serial killer reincarnated as a girl solves crimes! One day, Nanaka, a girl in her twenties who runs an "exorcism shop," is asked to check on a distant relative, where she meets a strange girl named Riru. She is asked to investigate a case that is not really psychic-related, but rather a so-called "human mystery". As she listens to her clients and searches for the mystery of their cases, Riryu, whom she has taken on as her assistant, uses her special talents to solve one human black-hearted case after another. She has a calm manner of speech and thinking that one would not expect from a 10-year-old girl, and above all, she has the judgment of a criminal who seems to know all about the thoughts of people who become criminals. ...... So inside her is a reincarnated serial killer who was once executed for his crimes.

少女に転生したシリアルキラーが事件を解決へと導くサスペンスミステリー!除霊師、という名の実質「何でも屋」を営むアラサー女子・奈々圭(ななか)は、ある日遠縁にあたる親戚の様子を見に行くように頼まれて向かった先で、奇妙な少女・莉流(りる)と出会う。依頼される内容は実際に心霊関係の事件はほとんどなく、いわゆる「ヒトコワ」な現場に遭遇することが多い。相談者の話を聞いて事件の謎を模索する中、助手として引き取った莉流が持つ奇特な才能によって人間が持つドス黒い事件を次々と解決へと導いていく。とても10歳の少女とは思えない落ち着いた言動や考え方、何より犯罪者となる人間の思考を知り尽くしたかのような判断力、……そう彼女の中にはかつて死刑でその身を滅ぼしたシリアルキラーが転生しているのだった。