In a world composed of continuous ravines and smoky villages in the Loess Plateau, half-grown boy Shitou looked at the dark blue distant mountains on the horizon every day, and his heart was full of curiosity about the world outside the mountains. He was used to seeing the daily cycle of villagers going to the fields at sunrise and returning home with dust at sunset. He heard his grandfather talk about the "iron-skinned worms" smoking outside the mountains. While riding the train, he never knew whether the other side of the mountain was a higher mountain, a flat plain, or lights as dense as stars. This longing for the unknown became his most persistent dream in his ordinary life, and also quietly planted the seeds of leaving the Loess Plateau.
