In a town shrouded in thick smoke, where the skies are perpetually obscured and stars are thought to be mere myths, a young, imaginative boy named Lubicchi lives with the hope of proving the stars' existence to his skeptical peers. Despite facing ridicule, Lubicchi holds onto the stories told by his father before his mysterious disappearance. He finds solace in a strange and unlikely friendship with Poupelle, a sentient creature made of garbage who suddenly appears in their chimney-ridden town. Their bond deepens as they set out on a daring journey to uncover the truth about their world, driven by the belief that there is more beyond the clouded sky.

As Lubicchi and Poupelle venture through their industrial world, they face mounting challenges from those eager to maintain the status quo. The duo challenges rigid societal norms while overcoming personal fears and prejudices. As they unravel secrets of the past and the true essence of Chimney Town’s existence, they inspire hope among people around them who have long forgotten to dream. As danger looms, the importance of friendship, courage, and hope takes center stage. Through discovering what lies beyond the smoke-laden atmosphere, Lubicchi learns about the power of persistence and the significance of seeing beyond the present constraints to reveal the hidden wonders of their universe.