A murder occurs at a party hosted by Dr. Aida's former students (mostly women), most of whom live in Kanagawa Prefecture. Dr. Aida is invited to the party and, at the request of his former students, decides to become involved in the case. Soon after, detectives from the local police department arrive (always accompanied by the chief of police), and a little later, Lieutenant Suda from the Fujisawa North Police Station (now the Yokohama Port Police Station) arrives to begin questioning the people involved (Dr. Aida secretly overhears this). The murders continue and the case becomes more and more confusing. Dr. Aida gets hints from the tools of the ancients that he has unearthed, and unravels the trick that was used to commit the crimes. The birth secrets of the people involved are the key to the case, and Dr. Aida (or Suda) always visits the obstetrics and gynecology clinic in the interview scene in the middle of the story.