Entropy is the thread running through this film, from the first moments after the Big Bang 13.7 billion years ago to the cold, dark end predicted for the cosmos. The film builds its case for the second law of thermodynamics using evidence at wildly different scales: ancient solar calendars built in Peru to track time by the sun, and a present-day Patagonian glacier shedding a million tons of ice a day as it collapses into the sea. Physicists and cosmologists explain how the same one-way arrow that melts glaciers and ages stars also governs galaxies, black holes, and the eventual fate of every particle in the universe. The narration moves outward from Earth to deep space, tracing how stars form, burn out, and leave the universe progressively colder and emptier. It is a slow argument about inevitability, using ice, ruins, and starlight as its evidence, and it ends with the bleak arithmetic of heat death rather than any reassurance.