A flight over the desert leads us to a highway, splitting the landscape. In its center, a bright, dazzling yellow line. Following this line, we find machines that roam across the veins and arteries of Los Angeles. Tirelessly, they paint, and repaint the line, in an endless roundabout. We encounter the men who work the machines and reflect on their particular role in society, contributing to the fascinating fabric of a gigantic city spreading over the world.