The story begins with Nausicaä, princess of the Valley of the Wind. A pilot, scientist, and explorer that can communicate telepathically with other living creatures, Nausicaä finds serenity and beauty within the Sea of Corruption. Humans cannot venture into this vast fungal forest without masks due to a deadly miasma produced by the resident flora. During an excursion, Nausicaä encounters her mentor Yupa returning home from distant lands. He offers her a small creature that he saved from hungry insects of the forest, a fox-squirrel Nausicaä names Teto.