Choose a Female Ghost or a Policewoman?

A genius detective who has repeatedly solved major cases was demoted to a small town one day. He originally planned to live a leisurely life, but he was forced to be involved in danger because of a shrewd female ghost he met on the first day of work. One person and one ghost worked together to solve difficult cases and captured criminals one after another. When the female ghost disappears, where should he go? This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.