"Nausicaä of the Valley of the Wind" is set in a post-apocalyptic world where human civilization has been devastated by a catastrophic event known as the "Seven Days of Fire." The planet is now covered by the Toxic Jungle, a vast forest filled with poisonous spores and inhabited by giant insects, including the Ohmu, massive armored creatures with a hive-mind intelligence. The remnants of humanity struggle to survive in isolated settlements, often in conflict with one another and the encroaching jungle.

The protagonist, Nausicaä, is the princess of the Valley of the Wind, a small, peaceful kingdom that has managed to coexist with the Toxic Jungle. Nausicaä is a compassionate and courageous leader, deeply connected to nature and possessing an extraordinary ability to communicate with the insects of the jungle. Her people live in harmony with their environment, relying on wind power and respecting the delicate balance of the ecosystem.

The story begins when an airship from the militaristic kingdom of Tolmekia crashes in the Valley of the Wind, carrying a dormant Giant Warrior, a bioweapon from the ancient war that caused the Seven Days of Fire. The Tolmekians, led by Princess Kushana, invade the valley to reclaim the Warrior, intending to use it to destroy the Toxic Jungle and reclaim the planet for humanity. Nausicaä opposes their plan, recognizing the catastrophic consequences of reigniting the ancient weapon and the importance of preserving the fragile balance of the ecosystem.

As the conflict escalates, Nausicaä embarks on a journey to prevent the destruction of the Toxic Jungle and the annihilation of both humanity and the natural world. Along the way, she encounters various factions, including the Pejite, another kingdom seeking to exploit the Giant Warrior for their own purposes. Nausicaä's journey reveals the deeper truths about the Toxic Jungle, its origins, and its role in the planet's recovery from humanity's past mistakes.

The narrative explores themes of environmentalism, the consequences of human hubris, and the potential for coexistence between humanity and nature. Nausicaä's unwavering empathy and determination to protect all life, human and non-human alike, drive the story forward, culminating in a resolution that emphasizes the importance of understanding and harmony over destruction and domination. The series presents a richly detailed world, complex characters, and a thought-provoking exploration of humanity's relationship with the natural world.