The story opens during the last days of the second Shogun, who has two sons, Iemitsu and Tadanaga. Iemitsu is the elder son and is expected to become the next Shogun. However, the real lion's share of the power is held by the Shogun. The Emperor, who belongs to the Noble class must approve the selection of a new Shogun. This rules governing behaviour for the Nobles are distinctly different from the rules for the Samurai. The main goal of the Nobles is to restore the true governing power to Japan to the Emperor. To accomplish this goal, the Nobles feel the more chaos the better. The Yagyu Conspiracy retells the one of the most exciting and intriguing chapters found in Japanese history...