Renka Houjou is the empress of Tokyo, which is a independent empire.

Renka Houjou is an empress that heads the empire that spreads from Okutama to the northwest, Edogawa Ward to the east, Izu•Ogasawara Islands to the south, with a land area of 2187.58 square kilometers, population 13 million.

This is the story of a regular boy Saionji Kazuto succeeding the throne of the Empire of Tokyo.

(Source: official website)