TANGO BOUNDED TOWARD HIM, THROWING UP THE SNOW all around her.

Mark Aker praised the dog and signaled Walt to stop and be still. In the shifting light from their headlamps, Tango circled Aker, tripping over the rear spines of his snowshoes, and sat down excitedly on his left side. Soaking wet and panting, she sank into the snowdrift up to her chest, her whole attention fixed on Aker.

She’d returned only once, forty minutes earlier. On that visit, she had circled Aker twice and then charged back into the dark, following the dull impressions of prior skiers and her own fresh tracks. This was her message to her handler that she’d found nothing.

At that time, Aker had made a point of asking Walt to bump the location into his GPS, knowing it might prove useful later.

But now, with Tango’s second return, Mark stood perfectly still, waiting to see what the dog had in mind. Tango stabbed her wet nose into his left glove. She sat back down, then stood up and stabbed his glove again.

“She’s found someone,” Aker said, rewarding the dog with a treat from his pocket and lavishing praise on her. Tango immediately ran out ahead of them, stirring up her own tracks. She glanced back, her eyes a luminescent green in the lights, and was gone.

The two men trudged off, impeded by the cumbersome snowshoes and limited by their own exhaustion. Walt reported the news and their position to the others but did not call them back. It was critical they find the missing skier, and, until he had more than a dog’s excitement, he wanted the search continued.

“No word from Randy,” Walt called back to Aker.

“Fucking radios,” said Aker, huffing so hard he could barely get a word out.

Walt pulled ahead of Aker as he followed Tango’s path through the snow. He snaked his way through a copse of aspen, the barren limbs, gray-white tree trunks, and shifting shadows unusually beautiful in the constantly moving light from his headlamp. His breath formed gray funnels. His thighs ached from dragging the sled, from lifting and planting the snowshoes, the effort clumsy.

Tango’s time between her returns warned of a long hike. She would head directly to the target, then return to her handler, before repeating the circuit as often as necessary. She would not stop until her arrival back at the target; then, missing her handler, she would return the full distance, give the hard indicator again, and take off once more. The process, known as yo-yoing, would continue until she led her handler directly to the hard target. Walt calculated that the missing skier was somewhere between twenty and thirty minutes away for her. For a man hiking in snowshoes, it could be double or triple that-an hour or more. He paced himself. Endurance was everything now. Walt was already conserving energy in order to get the missing skier back out of the wilderness.

He came by his wilderness skills honestly, not through textbooks or seminars. He’d grown up in these mountains. With a dad who worked for the FBI and moved the family every two to four years, the Wood River Valley had been his real home. He’d seen it change from a sleepy little destination ski resort into the fashionable, celebrity enclave it had become. And he’d grown with it, finding backcountry skills and survival tactics that had served him well for the past twenty years.

He ate a PowerBar and gulped down some icy water, foregoing the small thermos of coffee-the caffeine was welcome but not its dehydratingeffects. He reviewed the work ahead: medical treatment, if they were lucky; sledding him out; recalling the team; getting back down the snow-covered highway to the hospital. It was anything but over.

When he next checked behind him, he’d lost Mark to the storm, so he waited, as the snowflakes changed from nickels to quarters, suggesting warming. It was the one thing he didn’t need right now. If the snow went to slush, the mountain went to concrete and would be more prone to slides. He switched off his headlamp and peered into the dark, finally spotting a pinprick of flickering bluish white light in the distance: Mark. Moving considerably slower. He was weighed down by more than just the backpack and physical exhaustion; Walt knew something was troubling him. It took him back to Mark’s mention of politics-a conversation that had been interrupted.

Tango streaked past Walt, bounding down the hill for Aker. Wet, and breathing hard, she passed Walt a few minutes later, charging back up the hill. She was still on the target. Walt checked his watch, bumped the GPS, and estimated the missing boy was now less than ten minutes away.

The moment Aker reached him, Walt headed off, following the dog’s zigzag route as it traversed the steep snowfield. He now took a more vertical path, connecting the dog tracks, but climbing more steeply, the steady climb driving his heart painfully.

He pulled a heavy, six-cell flashlight from his pack. Its halogen bulb produced a sterile, high-powered light, which, catching the edges of forest to their right and left, revealed that the snowfield narrowed, ending in a rock outcropping, now a hundred yards straight up.

The Drop.

“Doesn’t… make… sense,” Aker said, huffing as he caught up. “We should have seen Randy by now.”

In the excitement of the find, Walt had forgotten about Randy. “It’s possible he found fresh ski tracks, leading into the trees or something,” Walt said. “We wouldn’t necessarily see him in the trees.”

But he was thinking back to that earlier, unexplained sound, and knew Mark was too.

Now, as they ascended together, Walt’s flashlight suddenly caught the eerie glow of animal eyes at the base of the towering rocks. Tango. Her position there suggested a fall.

“Damn,” Mark said.

“Yeah.”

Despite the drag of the sled, Walt pulled ahead of Aker. People survived falls into snow, he reminded himself, wondering if maybe Randy had fired that shot they’d heard earlier.

Tango bounded from a hole she’d dug deeply in the snow. She raced past Walt to the trailing Mark Aker; then she streaked past Walt on her return.

Walt arrived to her flurry of digging and trained the beam into the hole.

He glanced back at Mark and raised his hand. “Stop there!” he shouted.

Aker ignored him and arrived at Walt’s side just as Walt switched off the flashlight.

But Aker’s headlamp found the twisted human form in the snow. Randy’s head was raked fully around, pointed horribly unnaturally over his back like an owl’s, his open, still eyes crusted with ice crystals.

Walt was the first out of his snowshoes. He jumped down into the pit dug by the dog and quickly searched the body for a gunshot wound. But there was no blood, no wound visible. Yet they’d heard a gunshot; he felt certain of it.

Mark was on his knees, sobbing. The snow fell around him like a curtain.

Walt climbed out of the hole and dropped to his knees to block Mark’s view of the body. He opened his arms and pulled his friend to him. The sobbing came uncontrollably then.

Tango circled them, whining, with her nose to the hole, her innate empathy steering her nearer and nearer to her master until pressing up against him tentatively and then nuzzling in, as if to keep Mark warm.