Year Taisho 20, Kuzunoha Raidou the 14th returned to the Capital as the Protector of the Capital. He stayed in Narumi Detective Agency as a cover for his true job. He was partnered with Gouto-douji, a black cat.

One day, series of strange murders came. The victims were strangely killed, as if they were eaten by a beast. Then, Tae Asakura, their friend, came in and said about a person that is most likely to be a victim. Tae came to the man and wanted to investigate further. Raidou had a bad feeling and came to investigate, but the man was possessed by a demon. He almost killed Raidou, but the body fell down. Only left an empty skin. Raidou knew immediately that the demon was out there. Manticore's the name.
Raidou had no choice but to defeat it. After he defeated it, he found Tae, almost unconcious. Gouto said that the man shouldn't be able to summon a demon because he's not a summoner.

Someone mysterious is responsible for all this. Although the serial killing stop, the mysterious man is still out there. This mysterious man called out the Marebito Project. He knew that Raidou was the great obstacle for him.

How will things turned out? What is this Marebito Project?