an uneasy balance settles among the four kingdoms, maintained mostly by the military genius of tianji's general qi zhikan and the political acumen of tianxuan's deputy prime minister, gongsun qian. to everyone's surprise however, a fifth nation, nansu, reveals itself when its king, yu qing, requests official recognition from the other four kingdoms. as the four swordsmen travel to nansu, shifting alliances, deep emotions, and a carefully-laid conspiracy of revenge spur the world towards war.