It spends two hours choking you on soot so that one glimpse of a star lands like a punch. Studio 4°C builds Chimney Town as a tactile nightmare of grime and gaslight, then drops a garbage man with a beating heart into it, and Poupelle's patched-together bulk somehow moves with more warmth than any human in frame. The real cruelty is the system: a 4,000 meter wall, inquisitors who treat the word 'sky' as heresy, and currency engineered to rust so nobody can ever save enough to leave. Lubicchi refusing to stop believing his father Bruno wasn't a liar is the whole engine, and the film knows exactly what it's doing when it makes the town's laughter hurt worse than the beatings. Then the heart's origin lands, and the smoke finally parts. You'll be a mess about a trash monster. That's the deal.
A sprawling metropolis choked by endless smoke from countless chimneys keeps its residents trapped in perpetual twilight. The massive wall surrounding Chimney Town stretches so high that no one remembers what sky looks like, or if it exists at all. Most have stopped wondering. On Halloween night, a delivery courier drops a human heart during the festival chaos. He searches through the suffocating haze but abandons hope, leaving the precious organ behind in the grime and shadow. Yet the heart refuses to stop beating. Alone in the smoke, it becomes something more than flesh and vulnerability. It becomes a symbol of connection, of life insisting on meaning even when everything feels disposable and lost. What begins as a tragic accident transforms into an unexpected journey. A living heart wandering through a dying city forces both the town and its inhabitants to confront what they've surrendered to survive. Beautiful and melancholic, this story asks whether hope can bloom in the darkest places, and whether one beating heart can change everything.