The experienced climber is well above 8,000 meters when the initial wave of atrophy occurs. The early symptoms are quite subtle – narrow breathing, cramping limbs, perhaps the sudden, stilted loss of equilibrium. One is well within the summit push come this point, trapped inside what seasoned vets might call the Death Zone. Pressing onward causes lungs to swell, the air now thin and weakened to a point where one is breathing through fixed tubes. Meanwhile, the frost is seeping in through numb extremities and stiff toes have given way to midnight blue. Looking up, the line of sight becomes obstructed, blurred by frozen goggles and snow-blindness. And yet, one presses on, beyond the serac and the snowdrifts, beyond the avalanche and ice, beyond the setbacks and the casualties, beyond it all until one stands upon the summit.

And that, my friends, is when the real mortal danger almost immediately sets in.        

For it is upon the steep descent that 75% of all fatalities occur. It is upon the steep descent that one in four climbers go dying. And it was upon the steep descent that the lion’s share of 11 professional mountaineers met their death during a weekend climb during the summer of 2008. Twenty-two climbers started up. Only 11 came back down.

The Summit provides a fairly breathtaking – if not slightly disjointed – job of chronicling the events that led up to and through that landmark expedition. I suggest that you go see it in a darkened theater, with no distractions and no cell phones. Otherwise, you won’t actually be seeing it at all.

(The Summit opens this Friday at the Landmark Sunshine Cinema and Lincoln Plaza in New York City.)