Utopa

Centuries after the 20th century, nuclear and biological warfare has left the Earth in ruins. The planet’s ecosystem is collapsing, most life has vanished, and the world teeters on the edge of the "Big Six" - the sixth mass extinction. To survive, humanity retreated to floating cities in the sky, bringing along the last remaining plants and animals. Over generations, these creatures evolved in isolation, gaining human-like traits through genetic engineering: speech, upright walking, and thriving civilizations. The world below has long been forgotten. But when a mysterious seed drifts into one of these sky cities, three children - Kui, Hiruma, and Root - stumble upon it. Drawn by curiosity, they embark on a journey to the forbidden surface, unaware that stepping onto the ground will seal their fate, leaving them no way back.