Climate change is the subject, but the film's real focus is why decades of scientific warning have failed to produce action. It lays out the physical evidence for a warming planet, then turns to the political and industry pressure that has stalled policy, from fossil fuel lobbying to the gap between what governments promise and what they do. The film's clearest scenes follow organizers and activists building toward what they call the largest climate rally in history, timed to coincide with a United Nations world climate summit, coordinating marches and turnout across multiple cities at once. Scientists and campaigners appear on camera making the case that the window for limiting damage is closing, while the footage of rally planning grounds the argument in the mechanics of actually getting people into the streets. The film treats the science and the organizing as two halves of one story: what is known, and what it takes to make governments act on it.