Edo-period Japan remains strong and proud, decades after its imminent doom was prophesied. The new shogun, Yoshimune "Nobu" Tokugawa, encounters a variety of traditions that, in her modern judgment, make little sense. An epidemic rages exclusively among men, resulting in men comprising only one-fifth of the population. Nevertheless, three thousand young, agile, and beautiful men serve in the Oooku—the shogun's Inner Chambers. To uncover the origins of the existing hierarchy where women head their families and govern the nation, Nobu reviews the chronicles of the strange disease. Customs and traditions have changed to accommodate the plague; these new laws dictate the current culture and reflect the cruel story of the first female shogun, Iemitsu Tokugawa. Most notably, these customs seem to trace back to the moment a young monk, Arikoto Madenokoji, must abandon his way of life and devote his remaining days to the shogun and her Oooku.