Endurance athlete Richard Parks sets out to climb Mount Everest without supplementary oxygen, using the expedition to test whether extreme exercise can help stave off dementia. A team of scientists joins him for part of the ascent, rigging him with sensors to gather what the film says is the first real data on how the body and brain respond to climbing at extreme altitude. The cameras follow the acclimatization process through the Khumbu Icefall and the higher camps, tracking Parks's oxygen saturation, cognitive tests, and physical deterioration as the air thins. Interviews with the scientists explain what they are measuring and why the brain's response to hypoxia matters far beyond mountaineering, tying the climb back to dementia research happening at sea level. The film balances mountaineering footage, tension over weather and route conditions, with the science team's running commentary on Parks's numbers, making the summit push as much a physiology experiment as an athletic feat.