Through the branches of the gigantic World Tree, Pierig searches for the source of the malevolence that poisons the sap. The colossal branches of the World Tree are home to many diverse clans of people, each living among their tier. When Pierig, a Sap Diviner, is captured by the Bellicose clan for his rare skills, he learns that the World Tree is dying and its nourishing sap, the fuel for each of these communities, is being poisoned... Accompanied by three warriors, Pierig is forced to trace the origin of the evil that is eating away at the plant titan through each of its levels, and down to the very base if necessary. But along his journey, issues deeper than the root of this sickness begin to surface, putting everything Pierig knew to be true into question.