Amir Bar-Lev has been making documentaries for more than 25 years in all kinds of genres, but the Tillman Story and Long Strange Trip director never thought he’d approach the category of mountaineering. He had some personal issues with the field on a cinematic level and knew nothing about it on an informational level. Then a producer with whom he’s worked before got him up to speed on the chaos that happened around six years ago at Pakistan’s K2, the second highest mountain on Earth, and told him she saw him as the right person to tell the story.

The Last First: Winter K2 captures the frenzy around a group of mountaineers’ attempt to become the first people to ascend the mountain in winter — essentially, completing the last epic “first” that exists for the extreme sport. Some people fall in love; others die in pursuit of the goal. The project came to Bar-Lev with a ton of material captured on the ground already licensed, from potential documentary footage to videos made on iPhones and GoPros.…