A trio of Tokyo-based auditors set out to review the accounts of the city of Osaka and its affiliated agencies. They found that the government will give "OJO Assoicaition" in Osaka city 5 billion yen every year. There is no record about it. What is the "OJO Association?" They want to find out the truth.

In their survey, they met two junior high school students. A man-like girl and boy who loves to wear sailer suit.

On May 31st at 16 pm. Everything stops in Osaka. All the Osaka men go to the same place and want to protect their princess. The secret Osaka country are hidden under the Osaka Castle. They stay there over 4 hundred years and the propose is to protect the Toyotomi blood. It is the ties between Osaka men. Before their father is going to die, they will invite their son to walk the long way under the Osaka Castle and tell them the history of Osaka country and their duty to protect Princes Toyotomi.

All they want is to keep the connection with Toyotomi time and the trust bewteen father and son.