Upon arriving in the modern world, Akechi Mitsuhide had lost her memory and has since become a police detective alongside her assistant, Kibayashi. She is brought on to investigate the murder of a girl named Ayako Hototogisu who was found naked and beheaded with a knife in her chest. As they whittle down their suspects, Mitsuhide becomes bothered by a masked person named Morilanty who shows up to observe the crime scenes. Coming to a realisation, Mitsuhide chases after Morilanty, discovering her to be Kibayashi, with the real Morilanty posing as her assistant...