In a long-ago war, humankind set off a devastating ecological disaster. Thriving industrial 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 edge 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 Nausicaa.