"Miyori no Mori" is a manga series that centers on Miyori, a young girl who moves to a rural village to live with her grandparents after her parents' divorce. The village is surrounded by a dense, ancient forest believed to be inhabited by spirits and supernatural beings. Miyori, initially skeptical and withdrawn due to her personal struggles, gradually discovers that she possesses the ability to see and communicate with these forest spirits. This ability marks her as the "Forest Guardian," a role that carries the responsibility of protecting the forest and maintaining the balance between the human and spirit worlds.

The forest itself is a central element of the story, depicted as a living entity with its own will and history. It is home to various spirits, including mischievous kodama, powerful deities, and malevolent entities. As Miyori learns more about her role, she uncovers the forest's deep connection to the village and its inhabitants. The villagers, unaware of the spirits, rely on the forest for their livelihood, but their actions sometimes threaten its delicate ecosystem. Miyori must navigate the tension between human needs and the forest's preservation, often mediating conflicts between the two worlds.

Key characters include Miyori's grandparents, who provide emotional support and guidance, and a boy named Kippei, who becomes a close friend and ally. Kippei, though initially unaware of the spirits, plays a crucial role in helping Miyori fulfill her duties. The spirits themselves are diverse, ranging from benevolent guardians like the wise tree spirit Oyakata-sama to antagonistic forces that seek to disrupt the balance. Each spirit has its own motivations and backstory, adding depth to the narrative.

The plot explores themes of environmentalism, the coexistence of humans and nature, and the emotional growth of its protagonist. Miyori's journey is one of self-discovery, as she learns to embrace her role and confronts challenges that test her resolve. The story balances moments of whimsy and wonder with darker, more serious undertones, reflecting the complexities of the forest and its inhabitants. Through its rich mythology and character-driven narrative, "Miyori no Mori" offers a compelling exploration of the interplay between the natural and supernatural worlds.