Set in a fictitious feudal society, the massive island of Sengoku is constantly at war with itself, each of its five kingdoms battling for conquest over the land. When a dark scheme emerges from the shadows and results in the death of his kingly father, Namikawa Tatsuya flees northward to Aeros, where he is to encounter some of his greatest companions and his most vile of enemies. Lead by a naïve young lord named Date Masamune, Tatsuya must earn the One-eye'd Dragon's trust before he can have any other thoughts about restoring his ruined family, nevertheless bringing peace to the entire region.