When William Merrick of the U.S. Consulate in Hakodate Japan is tasked to rescue a group of shipwrecked Americans en route to the Shogunate Capital of Edo, he unwittingly becomes swept up in a deadly plot by a secretive faction whose aim is to overthrow the Old Order of the Tokugawa Shogunate whose dwindling 266 year rule is under threat from open rebellion and all out civil war. In a feudal land ruled by powerful Samurai Warlords divided by loyalties between their Emperor and Shogun, the balance of power and the future of an Empire rests with one man under The Setting Sun.