In the face of an impending drought, the Star Readers of the Shin Yogo Empire scramble to avert a famine. Legend tells of how the first emperor and eight warriors vanquished a water demon to prevent a catastrophic drought, securing the future of Shin Yogo. Now, as a water demon resurfaces within the emperor's own son, Prince Chagum, a grim decision is made to sacrifice Chagum for the empire's well-being. Enter Balsa, a skilled mercenary armed with a spear, who intervenes just in time to thwart an assassination plot against Chagum. Tasked by Chagum's mother with safeguarding him from the emperor's forces, Balsa honors a sacred promise and embarks on a perilous journey. Seirei no Moribito delves into Balsa's quest to shield Chagum, delving into themes of nature's wonders, the essence of family, and the unexpected connections that blossom between individuals.