In the year 1716 a mysterious epidemic strickens the country of Japan, dropping the population of men to 1/4th of its prior state. With the drastic reduction of men, more and more families struggle to maintain in Japan. While more and more males are sought out for their ability to produce children, a 19 yr old young man named Unoshin Mizuno (Kazunari Ninomiya) hopes to marry childhood sweetheart Onobu (Maki Horikita). Due to class differences he realizes this is almost impossible. To raise his social status and also save his poor family, Unoshin Mizuno enters the Ohoku (inner chambers of the Shogun's castle) and attempts to vie among 3,000 other men for the affection of the female shogun. What Unoshin Mizuno quickly learns about the Ohoku is that the men there are all beautiful, but highly ambitious and conniving. In this environment, the 7th shogun Tokugawa passes away and the new shogun Yoshimune Tokugawa (Kou Shibasaki) takes the throne and enters the Ohoku...