Hoshou Reiko is a rich heiress who works as a novice detective, but she's not very good at deducting. Her butler, Kageyama, doesn't hesitate using his sharp tongue against her. Together, they will solve different cases as their relationship develops.
Both are about a rich heiresses who decides to become a detective. She solves murder cases. Both heroines were never troubled about money and other things, therefore even after revealing the culprit they can never understand their motive. They tend to lecture the murderer after finding him.
In Fugou Keiji the lady finds the murderers alone, while in Nazotoki wa dinaa no ato de the butler does most of the thinking.