In a post-apocalyptic future where a toxic jungle, filled with mutant giant insects, threatens the remnants of humanity, small peaceful kingdoms struggle to survive and coexist with the treacherous environment. The story follows a young princess named Nausicaä from the Valley of the Wind, an agrarian kingdom on the outskirts of the jungle. She is compassionate and adventurous, with a unique ability to understand the creatures of the toxic forest. Nausicaä explores the jungle and the Sea of Decay, seeking to understand its ecology and find a balance between humans and nature. Her inherent curiosity leads her to uncover the mysteries behind the forest's origin and its purpose.

As the tale unfolds, warring nations vie for power, desperately seeking ancient weapons to dominate the decaying world. An airship from the military kingdom of Tolmekia crashes into the Valley of the Wind, carrying an ominous cargo that could reignite catastrophic warfare. The crash draws the Tolmekians to the valley, led by the imperious Princess Kushana, who aims to use the cargo to eradicate the toxic jungle. As Nausicaä endeavors to protect her people and their way of life, she is thrust into the conflict. With diplomacy failing, she becomes entangled in a struggle that could determine the fate of the world, challenging her beliefs and spurring her into actions that might bridge the divide between humanity and the misunderstood ecosystem of the jungle.