Nona, a young boy, flees city life after growing disillusioned with his duties at the Time Bureau, an institution governing temporal matters. He roams the desert until meeting the witch Niinya, who proposes a fresh start on her farm. Accepting, Nona embraces solitude at her remote farmhouse, cultivating a garden and vending produce at the market. Niinya departs each dusk and returns by morning, leaving him mostly unsupervised.

During a market trip, Nona's cart fails in the desert. He discovers merchants Scopello and Makinso beside a trackless, stationary train. They peddle planets encased in earth-like clumps. Nona barters his vegetables for the smallest planet's seed. Back at his shed, he plants it in a pot, tending it with soil and spray-bottle water.

Under moonlight, the seed levitates and spins, triggering a genesis akin to planetary birth. Mist from Nona's spray coalesces into clouds, unleashing rain and lightning that forge primordial seas. The planet consumes soil from the pot, expanding as grass seeds sprout and a pill bug emerges—the first life. Nona watches intently, swathed in a blanket through nights in the shed, observing the evolution like a creator surveying their realm.

As the planet swells, chaos engulfs Nona's environment. Niinya compels him to bid farewell to his creation. When the merchants reappear, Nona releases the planet into a galaxy of similar celestial bodies, where it matures into a complete world.