Summit season is about to start at Everest Basecamp, and the doctors working at the highest hospital in the world gear up to deal with a constant stream of life-threatening emergencies. With hundreds of climbers about to enter the death zone, it is only a matter of time before Everest claims its first casualties.

At the foot of Mount Everest, a climber comes into the basecamp clinic at death's door. Can the doctors save his life and fly him out? As the Everest summit season gets underway, climbers are exposed to a lethal range of high-altitude illnesses, trauma and frostbite, and the world's highest clinic gets busier and busier.

At the world's highest hospital at Everest Basecamp, volunteer doctors treat the first major frostbite case of the season, and UK scouts head for summit glory. Perched in a tent on the Khumbu Glacier, the basecamp clinic is the frontline of high-altitude medicine where doctors battle to save the lives of climbers who run into trouble in the death zone.

At Everest Base Camp, a UK scout pays a painful price for reaching the top, and three climbers set off for a record-breaking second summit in seven days. With base camp melting and the monsoon approaching, is there still time to risk a final push to the top?