Giant craters start appearing across Siberia's Yamal Peninsula, blasted into the tundra with enough force to fling frozen earth for hundreds of feet. Scientists race to the remote sites by helicopter to figure out what caused them before the evidence melts or collapses back into the ground. The trail leads to methane, gas that has been locked in permafrost for thousands of years and is now escaping as the Arctic warms faster than almost anywhere else on Earth. Researchers rappel into the sinkholes to measure gas concentrations and take ice-core samples, piecing together how pressure builds underground until the frozen cap over it finally gives way. The film lays out what these craters mean beyond Siberia: permafrost across the Arctic holds an enormous reserve of carbon, and its thaw could accelerate the same warming that is causing it. Interviews with geologists and climate scientists frame the sinkholes as a visible symptom of a much larger, mostly invisible process happening underground across the far north.