"Mushi": the most basic forms of life in the world. They exist without any goals or purposes aside from simply "being." They are neither good nor evil, but their existence often intertwines with the human world in mysterious and sometimes life-threatening ways. Because most humans cannot see them, their effects are often mistaken for diseases, hauntings, or supernatural phenomena.

Ginko is a "Mushishi"—a Mushi Master who travels the Japanese countryside to research these primitive lifeforms and help people suffering from their influence. Each episode is a self-contained, hauntingly beautiful story exploring the delicate balance between nature and humanity. As Ginko wanders from village to village, he seeks not to destroy the Mushi, but to foster a coexistence that allows both lifeforms to survive in a world where the line between the physical and the spiritual is paper-thin.