THE SUMMIT "Shit. I forgot my Game Boy."

IF YOU WONDER what drives someone to want to climb mountains, look elsewhere. The documentary The Summit blows off any expectation that it might justify people risking frostbite and skull smashing in order to get a life-affirmingly fantabulous view. Director Nick Ryan is on a different, more specific mission: to sort out what went wrong in early August of 2008, when 11 people died trying to summit K2. K2 is the second-highest mountain in the world—coming only after Everest—but is far more dangerous than its rival.

Although many have died on K2, this particular disaster had a record death toll, and set off a firestorm of blame. That instinct to get angry when others purposely put themselves in harm's way hangs in the tension of The Summit—present but rarely spoken, as in archival footage of a landmark 1950s-era expedition that similarly vilified its survivors.

Seamlessly weaving back and forth between documentary and reenactments, The Summit walks its audience through the course of the disaster with a court trial level of detail. Adding to the complications, exhaustion and high altitude do ugly things to the brain—almost everyone who was present either has an account tainted by confusion and shock, or they're dead.

Ryan doesn't paint much in the way of added emotion onto this evidence-based account, but shuffles the inherently suspenseful pieces of the story into a sequence that compels the audience to walk into its ultimate motive: exonerating the social guilt lobbed at survivors who've been accused of abandoning their dying companions. These are circumstances in which it doesn't make sense to be a hero, and if there's one thing The Summit makes clear, it's the naked fact of tragedy. It may do so quite well—but the unanswered "why?" in your head when the film begins may loom even larger when it ends.