ONE LATE-SUMMER AFTERNOON in the high pastures of Pakistan's Rupal Valley, Steve House stuck his head out the door of his mess tent and glanced up at the cloud-cloaked mountain that loomed above. Eventually, House knew, the north wind would begin to blow, ushering in the first high-pressure system of the post-monsoon season, and everything would come clear. But it needed to happen fast. Already, ten days had gone by since he and his climbing partner, Vince Anderson, had come down from their final round of acclimatization.

What House was looking at, or trying to, was the colossal south face of Nanga Parbat, at 26,660 feet the world's ninth-highest mountain. Rising nearly 15,000 vertical feet from the valley floor, the Rupal Face, as it's more commonly known, is an impossible maze of rock towers, hanging snowfields, and ice, sometimes described as the biggest mountain wall in the world. "Imagine this," Reinhold Messner wrote in his 2002 book The Naked Mountain. "The east face of the Monte Rosa with the Eigerwand above and the Matterhorn perched on top."

It was Messner, of course, who first scaled the Rupal Face. In 1970, when he was just 25, he and his brother Günther (who would later die on the descent) led the push up a difficult route on its left side as part of a joint German-Austrian expedition. Fourteen years later, a second route, to the right, was established by another Himalayan legend, Polish alpinist Jerry Kukuczka, and three others. For House and Anderson, both 36, an obvious prize remained: the unclimbed Central Pillar, the Rupal Face's steepest, most direct line—and also, undoubtedly, its most difficult. And that wasn't all. Whereas previous teams had relied on "siege" tactics—methodically establishing a series of successively higher camps and using fixed ropes to move back and forth between them—the pair were committed to climbing alpine style, in a single bottom-to-top push.

House had attempted the face before. The previous summer, in 2004, he and another partner, Boulder, Colorado–based Bruce Miller, 43, had come very close to completing the route. They were five days up the face and less than 2,000 vertical feet below the summit when House, who had led most of the tough pitches on the way up, began to feel the effects of altitude sickness and slowed dramatically. After an agonizing hourlong discussion, Miller became convinced that House's life was in peril, so he persuaded his partner to turn around—a decision that House would later, and quite controversially, suggest was more a reflection of Miller's fear than of his own incapacity.

Meanwhile, others had set their sights on the Central Pillar. When House, Anderson, and two other American climbers, Scott Johnston and Colin Haley (who were there to attempt a previously climbed route on Nanga Parbat), had trekked into the Rupal Valley three weeks earlier, they'd found Tomaz Humar, the celebrated Slovenian alpinist, already ensconced at the prime base-camp location in Baseen Meadows, along with a small army of followers—a film team, a Web-site technician, even, according to House, an "aura reader." The Americans exchanged pleasantries with Humar and kept walking, eventually establishing a camp of their own in Latoba Meadows, a two-hour walk upvalley. "I wanted to be as far away from that circus as possible," House told me when I hiked in a few weeks later.

By then, the details of Humar's botched summit attempt had become the talk of the mountaineering world. The day after House and Anderson's arrival, the Slovenian had launched a solo bid up the middle of the face. He wound up stuck on rotten ice at 19,350 feet, pinned down by the weather and out of food and water. Nine days later, after a series of dramatic radio transmissions, Humar was snatched from the precipice by a daring Pakistani army helicopter pilot. The general consensus: The Slovenian had pulled a stupid stunt, endangered others' lives, and was lucky to have survived.

On my first night in base camp, as we dined on chapatis and a freshly killed chicken prepared by expedition cook Fida Hussein, House offered his own piquant analysis of his rival's misadventure. The way he saw it, Humar had been defeated not just by hubris and bad planning—he wasn't fully acclimatized and had set off despite a sketchy weather forecast—but by the overwhelmingly commercial nature of his expedition. It was "interesting," House said caustically, that Humar claimed to have run out of food and fuel but still had plenty of batteries to power his radio, "so he could do daily dispatches for the Slovenian national radio network, which just happened to be one of his major sponsors."

To House, a dedicated minimalist who argues that any extra weight—even that of, say, a video camera—could mean "the difference between life and death" on a long, tough route, the implication was clear: Humar was less a cutting-edge alpinist than a careerist profiteer.

House tipped his chair back and shook his head dismissively. "It's not like you need a lot of money to climb these peaks," he said, offering as evidence his own budget for six weeks in Pakistan: just $10,800, split evenly among him, Anderson, Johnson, and Haley. "I've never understood the whole argument for sponsored expeditions," he concluded. "To me, the money just gets in the way."