In a long-ago war, humankind set off a devastating ecological disaster. Thriving indistrial societies disappeared. The earth is slowly submerging beneath the expanding Sea of Corruption, an enormous toxic forest that creates mutant insects and releases a miasma of poisonous spores into the air.At the periphery of the sea, tiny kingdoms are scattered on tiny parcels of land. Here lies the Valley of the Wind, a kingdom of barely 500 citizens; a nation given fragile protection from the decaying sea's poisons by the ocean breezes; and home to Nausicaä.

Nausicaä embarks on an inner, spiritual journey to the heart of the Sea of Corruption, where she discovers its surprising secret. She returns to the land of the living, compelled to share her discovery, but Nausicaä accidentally awakens a God Warrior from its stasis.