On the second-to-last day of 2013, when the glow of Christmas had passed and there was nothing to do but settle in for months of unbroken winter, a stranger arrived in Saranac Lake, a 5,400-person mountain town 70 miles shy of the Canadian border. Set amid the patchwork of forest preserves and villages that make up the largest publicly protected area in the Lower 48, Saranac Lake is the self-appointed "Capital of the Adirondacks," a onetime best small town of New York, and the place where I'm from.

The stranger was a 31-year-old infantry captain in the Royal Australian Regiment who'd been diagnosed with post-traumatic stress disorder after returning from Afghanistan two years before. He arrived at 6 p.m. on the one bus that comes through town each day: an Adirondack Trailways coach that chugs slowly uphill from Albany, stopping in what seems like every podunk town along the way.

To get to Albany, he'd taken a bus from New York City, and before that planes from San Francisco, Sydney, Canberra, and, ultimately, Adelaide, Australia, his own hometown, more than 10,500 miles away. He was male-model good-looking—wholesome and tidy, with intelligent eyes—though he'd recently grown shockingly thin and had cut his brown, widow's-peaked hair so close it was nearly shaved.

He'd been a battle captain in Afghanistan's Uruzgan province, just north of Kandahar, working as part of a North Atlantic Treaty Organization coalition force. But his PTSD diagnosis had placed him on restricted status, and he'd since been re-assigned to a desk job in Canberra, Australia's sterile government seat. He had a medical review coming up in January and, his family would later tell the police, he feared he might be discharged. The Australian Defence Force was withdrawing from Afghanistan at the end of 2014, and the military was downsizing; everyone who remained had to be fit to deploy.

The bus let out in front of the shuttered Hotel Saranac, its six-story bulk standing dark and silent over the town. From what police would later determine, the man probably walked down Main Street, past the fogged windows of bars, under the yellow face of the town hall clock tower, then traced the curve of Lake Flower back in the direction from which his bus had come. He might have stopped in a liquor store and the shopping plaza at the edge of town, then walked a little farther down the road toward neighboring Lake Placid before turning around where the snowplows do, at the crossing of the old railroad tracks.

Somewhere around nine, he returned to one of the last motels he'd passed, a two-story Best Western, and asked the clerk how far the woods extended past town. Hearing the answer—nine miles to Lake Placid—he said he'd stay the night. At 10, he emerged briefly to use the lobby computer.

The next morning, on New Year's Eve, he bought a plastic shovel and a decorative fleece blanket at the shopping plaza and set off on foot. People would later say they'd seen him pass, dressed in snow pants and a black winter parka, and carrying a large, brown backpack as he walked toward the crossing. The snow was spotty due to a pre-Christmas thaw, but weather was coming. Weather was coming to the whole country, in fact, as a polar air mass—a vortex, meteorologists intoned—descended from the Arctic.

The railroad tracks cut through a marshy area, continued through the smattering of houses that make up the hamlet of Ray Brook, and passed the gates of the federal penitentiary. At noon, two guards on their lunch break saw a man in winter gear walking steadily east. Just beyond the prison was the trail to Scarface Mountain. Broad but not tall, with no real view, Scarface isn't majestic, but on the slope facing Saranac Lake is a distinctive, rocky cliff—its eponymous scar. From the trailhead to the summit, it's a 3.5-mile climb that takes around two hours in summer. In late December, it would have been slower going, the route covered by snow, criss-crossed with misleading animal trails, and slick with ice. At some point, the man walked off the trail and into the unmarked woods.

On a shoulder just below the scar, he stopped, and beside a cluster of mossy boulders laid down his pack, took out his plastic shovel, and began to dig in the frozen earth. With what had to be monumental effort, he cleared a narrow trench the length of a tall man's body. In the rapidly cooling evening, he stopped to eat tinned beef stew and downed two bottles of Winter Jack, a syrupy whiskey-laced cider. Perhaps just intending to rest, he covered himself with the thin moose-print fleece. One hundred feet ahead of him, the mountainside dropped off sharply. Beyond it, the sodium streetlights in town flicked on, glowing brown through the dampness that hangs in the air before a snow. At some point, he slashed shallowly at his wrists.

The snow came as predicted. I left my parents' house early on New Year's Day to beat the storm. On my way out of town, I passed the Best Western where the man had stayed, and where my brother James and I had both worked years ago; I stopped for coffee in the shopping plaza where he'd bought his final provisions; I crossed the tracks he'd walked down—tracks I'd skied earlier that week, admiring, as always, the two steel rails that appear to climb straight into the mountains beyond. Three days later, the news would hit the town paper: A young Australian named Paul McKay had gone missing in the North Country, last seen in Saranac Lake.

Paul's father had traced an email his son had sent him back to the motel, and called the Saranac Lake police. In the email Paul said that everything was OK, but that he had some "housekeeping issues" to clarify. What followed was a two-page list, transferring all of his belongings, from his car to his Kindle account, to his father. He authorized his parents to access his army email account and noted the amount of the military paychecks to be deposited to his bank until the event of his discharge. Inexplicably, he wrote about what would happen if his body was never found.

Saranac Lake's police chief at the time, Bruce Nason, wrote to Paul's banks for statements, urgently explaining that Paul might be missing in the wilderness, and that temperatures were 15 below zero and dropping. As the police knocked on doors in search of clues, the ink froze in their pens, and the people they interviewed were aghast at the idea of anybody being out in that cold.

Paul's bank records led to an ATM at a Greyhound terminal in Albany, where security footage revealed an image of him leaning on a counter as he bought his ticket north using a fake name. When a family member went to his apartment in Canberra, they found his military dress uniform and medals laid out at neat right angles on his bed, his army-issue sword standing at attention to its side.

Just before Paul disappeared, his family learned, he'd created personal profiles on LinkedIn and Facebook. Paul hated social media.

On the LinkedIn page, he specified that he'd served in Afghanistan alongside soldiers from the United States Army's 10th Mountain Division, based out of Fort Drum, New York, three hours west of Saranac Lake. And he noted that he was the battle captain on duty during "Bloody Saturday," the "green-on-blue" attack of October 29, 2011, when an Afghan coalition member opened fire on a group of 12 Australian soldiers and three of their interpreters on their shared base in Uruzgan, killing four and severely wounding nine. At the time, it was the single worst day the Australian military had seen since coming to Afghanistan.

The Facebook profile contained only photographs—Paul on military training exercises, Paul as a tourist in Asia, Paul in his olive-drab dress uniform, looking like he'd just stepped out of a World War II movie, and, for his profile image, a shot taken from a distance: Paul sitting atop a mountain, facing away.

Many who heard about Paul's disappearance inferred that he'd been present at the Bloody Saturday attack and had watched his colleagues die—that he had survivor's guilt or felt he'd somehow failed to protect them.

But it wasn't that simple, said two friends who'd been there, Army Captain Andrew Belkin and Air Force controller Laura Flint (last names have been changed). The attack had shaken every Australian in Uruzgan, they said, but Paul hadn't been anywhere near the outpost where the Afghan soldier opened fire. The provenance of his PTSD was something more ambiguous.

While some soldiers' trauma might trace back to a single event—a terrible gunfight, an improvised explosive device that blew up a friend—others' can be more cumulative, just pain and exhaustion built up over time. Some survive the horror of near-death experiences only to be set off by something seemingly trivial instead. "That's why they find it so hard to define, understand, and treat," Andrew said. "You can wire 100 people up and put them through the same thing, and they will all come out different. Because so many factors come into play: how kids are raised, what their intrinsic beliefs are, things that happened when they were a child that at some point shaped their view of the world."

Paul had grown up in Adelaide, the coastal capital of South Australia. It was a status-conscious city, and he attended the University of Adelaide—essentially an Australian Ivy—where he earned a double degree in law and commerce. He interned at the city's top law firms and for a local politician, whose life, friends said, he saw as a template for his own. When he went out for drinks with friends, he insisted they toast the Queen.

(Illustration: Corey Brickley)

In the long, mostly peaceful years after Vietnam, service in the Australian Army Reserve had become a gentleman's calling: part of a Renaissance man identity for many of the city's successful doctors and attorneys. Paul joined the Adelaide Universities Regiment of the Army Reserve in late 2004. While most reserve officers take two to three years to complete their training, Paul finished in just 13 months. He mapped out a glorious life plan: to excel in both the reserves and the law, to become a partner in a top firm by age 30, and to parlay that into a successful career in politics or business.

His friends believed he would do it. Paul was an overachiever—exceptionally disciplined and very smart, retaining facts so well that he suspected he had a photographic memory. In a country of sports fanatics, he played almost every game. "Many people have celebrities they look up to," said his childhood friend Peter O'Leary. "I looked up to Paul."

In 2008, Paul finished his law degree with honors and was admitted to the bar. It seemed he was on track to join Adelaide's officer-and-gentleman elite. And then, almost immediately, he quit.

He shifted his focus to the military. His goal: pass selection for Special Forces—the national equivalent of the Navy SEALs—and rise through the ranks, all the way to general. He spent six months training for the grueling, month-long selection course for the Special Forces' commandos, but ultimately wasn't chosen—told, friends believe, that he just lacked tactical experience and should re-apply after working with a regular battalion first.

In most circumstances, a reserve officer transferring to the regular army would be compelled to start anew, returning to military college for another 12 to 18 months. Only the most promising reservists were allowed to bypass the process, and at the time Paul applied, there were only two openings for direct transfers available. It surprised no one when he was chosen.

Saranac Lake seems to possess a sort of geographic anonymity, and the police were puzzled by the fact that Paul had even ended up there. While in recent years the town has gained traction as a tourist destination, locals still think of it as impossibly remote. "You don't just end up here," said my brother James, now a police officer in town, who helped with the search.

The police thought if they could figure out why Paul had come, it might help them get to him in time. They uploaded a missing person flyer onto Facebook, and within days the post was shared nearly 30,000 times. They began to receive tips from around the country: people who thought they'd seen Paul in nearby Saratoga Springs, or as far away as California. None of the leads panned out.

Paul's friends in Australia began to write too, telling a common story of an intelligent and driven man who'd dropped progressively out of touch. They worried Paul might not want to be found.

As information trickled in, possibilities emerged. Paul had served alongside a number of officers from upstate New York's Fort Drum, but it didn't seem that he had contacted anyone there. He was an avid military history buff who collected trivia about battlefields all over the world, but there were no real military sites near Saranac Lake. He was, one friend said, "ridiculously addicted to mountains" (and had even aspired to climb the Himalayas), but there were taller, better-known peaks almost anywhere else in the world.

Then there was the grimmer possibility. The Adirondacks, which the Iroquois and Algonquin called "the dismal wilderness"—deeming it unfit for human habitation—are one of the largest forested areas in the country. "If you wanted to come up here and disappear, you could," said Captain John Streiff of the New York State Department of Environmental Conservation.

People go missing every year, usually unprepared hikers or hunters who wander off the trail into the dark uniformity of the forest and can't find their way back. The walls of the DEC, home to the park's forest rangers, bear missing persons posters from decades past: bodies still believed to be somewhere in the woods.

More recently, rangers had seen an uptick in people who go into the woods not for recreation, but intending to do themselves harm. Nationally, suicide had become a leading cause of death in parks and open spaces. The pattern was striking enough in the Adirondacks that DEC rangers had requested specialized training for approaching people in mental distress. Just three months before Paul disappeared, a Massachusetts man had taken his life on a mountain 20 miles outside Saranac Lake. Several years before that, there'd been a troubled man who told his family he was going to a nearby mountaintop to watch the end times battle. Another had secreted himself within a dense thicket before shooting himself. Rangers and police began to speculate that perhaps Paul was just the latest troubled soul "to come to the Adirondacks to pass into the great beyond," as State Police Captain John Tibbitts put it.

But Paul's disappearance seemed to move people in town far more than other cases had. The newspaper printed his boy-next-door photo, and, in this community full of English and Irish surnames, he could have been anyone's brother or son. Locals wrote letters to the editor wondering whether Paul had somehow been drawn by Saranac Lake's peaceful mountains, or its kindly small-town ways. They referred to Paul with odd formality, as "Captain McKay" or simply "the Australian soldier": a sort of everyman wounded warrior.

Uruzgan, Afghanistan, is mostly desert and jagged mountains cut through with lush stripes of valley—the Green Zone—where watermelons, pomegranates, and wheat grow alongside the poppies. Though just one part of the U.S. war zone, Uruzgan was where all the Australian combat units were stationed. Australia's reasons for being there were indirect: not a matter of immediate national security, or even a quest for resources, but instead the duty of allyship. Whether or not most soldiers realized it, said Andrew Belkin, "We were fighting to keep the country relevant, to have a seat at the table with the U.S. and the Brits."

By April 2011, when Paul and Andrew arrived, Australian military members were there primarily to mentor the fragile Afghan National Army and focus on Australia's long-term plans for withdrawal. Both men were stationed at Tarin Kowt, the central headquarters of Combined Team Uruzgan, working in modular offices of reinforced metal. Andrew worked in long-term planning, and Paul was a battle captain in the command center: the nerve cluster of CTU, which oversaw all the different initiatives—mentoring, re-construction, support—happening across Uruzgan and the agricultural province of Daikundi to the north. As an operations briefer, Paul monitored developments in both places, and, to some extent, the rest of Afghanistan, reading through the hundreds of spot reports that came in each day. If a bridge collapsed somewhere, he'd decide whether that information was important enough to pass up the chain.

For at least six months, Paul worked the night shift. His whole job, said Andrew, was sitting in the command center and waiting for something to happen. Most of the time nothing did, and the team would pass the hours reading or watching television. But when something did occur—an attack on a forward operating base, soldiers killed—Paul was charged with making decisions about the initial response. He was "like an orchestra conductor," said Laura Flint, coordinating air traffic controllers, specialists in charge of supplies and artillery, ground forces, and medevac helicopters. It was a high-stress job.

Colonel Bob Akam, the commanding officer in Uruzgan, had spent most of his career serving as the officer in charge of an operations center, delegating responsibilities to battle captains like Paul. In Iraq, Akam had rotated his battle captains off the floor every month, for 60-day reprieves where they wouldn't have to sit and "see bad things all day long." But in Afghanistan, the staffing scenario was more complicated, and there wasn't the same manpower. The battle captains stayed where they were for months at a time.

And there were bad things to see. Akam had come to CTU in June 2011. In July, a band of Taliban insurgents tricked 20 schoolchildren and their teachers into pushing a broken car up the road, only to detonate a bomb hidden inside it when they reached the governor's compound. Individual soldiers were killed on patrol. Insider attacks were rising toward their 2012 peak, when they would account for 15 percent of all coalition casualties.

To Paul's friends in Australia, he'd seemed confident about his role in the army. But in the operations center, he was constantly ill at ease. He had conflicts with a senior officer who, one colleague remembered, sometimes put him in his place. His status as a former reservist who'd joined the deployment late marked him as an outsider, and he was sometimes derided for it. When he delivered his morning briefing, he bristled if someone made a joke, seemingly afraid he was losing control of the room. Paul compensated with meticulous formality. If Akam or another senior officer walked past his desk while he was working, Paul would leap up "as if the Queen had walked in," Akam recalled.

(Illustration: Corey Brickley)

Nevertheless, Akam saw none of the classic red flags of burnout—no drop-off in performance or muttered cynicism. Paul just never seemed to relax.

With Andrew and Laura, Paul was full of self-doubt, constantly pulling them aside to discuss decisions he'd made the night before, never sure he'd made the right call.

Then came the Bloody Saturday attack at Sorkh Bed Forward Operating Base. Paul was in the command post, manning the morning operations, and helped direct the evacuation helicopters that were dispatched within moments to the base.

Akam was boarding a plane in Kabul when he got the call from Paul: Shortly after 8 a.m., as 12 Australians and their Afghan interpreters walked across the compound, they came under sudden, heavy fire from a four-year veteran of the Afghan forces. Ten of the Australian soldiers, plus three translators, were shot. Days later, Paul would gather in an airport hangar with fellow coalition forces servicemen and watch as three coffins draped with the Australian flag were loaded onto a gray military transport.

Paul's response to the pressure and anxiety was to work even harder. While other night-shift workers tried to unwind, Paul pored over every intelligence briefing and situation report he could find. He shut himself in a separate room and returned to his military history books, searching out parallels between the situation in Afghanistan and ancient battles as though it was a puzzle he could solve.

By this point he was working 12- to 16-hour days, operating on little or no sleep. But change was coming. His unit was set to return home in February. In the third week of January, however, something happened. Australian officers who were there at the time said that word went around that Paul had "gone mad." When he went for a psychiatric evaluation, a fellow officer said, Paul admitted that he was thinking of harming himself. Within hours he was placed on a cas-evac—a medical casualty evacuation—and flown home.

Paul's family didn’t know he had left Afghanistan until he called from a psychiatric hospital in Brisbane and his mother went to collect him.

Back in Adelaide, he saw his oldest childhood friend, Peter O’Leary, and told him he wasn’t the same anymore. He'd taken to wearing a gold bracelet inscribed with the names of soldiers who'd died, and he looked at it constantly. He said he'd been pumped full of drugs and they were making him feel worse.

They ended up getting blind drunk, every shot no longer for the Queen, but for someone who died in Afghanistan. They walked from one end of Adelaide to the other, and when they staggered home, Paul had tears running down his face. They ran into two army acquaintances who asked Paul if he was all right: They'd heard he was on suicide watch. Peter started shouting at them to show a little respect, but Paul just stood there, leaden.

He told stories that were hard to confirm. Some had been reported, like Bloody Saturday. But he also said that he'd been jogging outside Tarin Kowt, was caught in an artillery strike, and had to hide in a tunnel for two days—which no one could corroborate. He told Peter that he'd seen things he wished he could tell him about, but that it would put his life in danger. Paul's ex-girlfriend suspected he was hallucinating.

He was put on a restricted medical status and posted to a low-stress position in Canberra, reviewing paperwork for equipment purchases.

One night in March, he sent a group text to a number of friends, saying he'd shamed himself and his unit; he seemed to be saying goodbye. Paul then walked to a nearby park and prepared to hang himself on a piece of playground equipment. His friends made panicked calls to each other, and Andrew alerted Paul's commanding officer. The CO called Paul's phone, Paul answered, and he ended up in the hospital. He was released, but soon tried again, this time a more serious attempt. He was sent back to the hospital and put under 24-hour surveillance. To a friend who visited him there, Paul lamented that his career plans were ruined: Why would the army want him now?

It was hard to pinpoint why Paul felt he'd shamed his unit. While many in the Australian media, and even Paul's friends, would later believe he blamed himself for the losses at Sorkh Bed, Colonel Akam said there was nothing about Paul's job that could conceivably leave him at fault.

A fellow officer believed that Paul's sense of failure was more personal: He'd failed his view of himself. "When you do nothing but succeed, it's very hard to fail," said the officer. People who aren't used to failing don't know what to do. "They don't know that you pick yourself up, that you learn how to go on."

Another snow came to Saranac Lake, followed by another thaw, eclipsing any hope that the search might be as easy as spotting a set of footprints leading off into the woods. Paul had been missing for five days when, on January 5, 2014, the Saranac Lake police briefed two forest rangers on the case. Ranger Scott van Laer, who lived just off the railroad tracks in Ray Brook, was appointed case section chief, setting the terms of the search. State Police helicopters were sent to hover overhead while rangers walked the tracks where Paul had last been seen.

Over decades of missing persons' searches, forest rangers had amassed an impressive amount of data to predict where various sorts of people—from children to senior citizens with dementia—will go. The people who want to be found almost always are: They make noise and leave clues. But another category of people they call "despondents"—those who go into the woods to self-harm—are not so easy to track. Rangers know that 80 percent of missing people are discovered on the same side of the road as their car; that most are found very close to where they were last seen; that despondents generally take the path of least resistance, following well-marked trails and avoiding thicker brush.

Going simply by the data, Paul should have been somewhere in the first half-mile off the tracks, near the prison gates. But the rangers had varying opinions on whether Paul would fit the pattern. Some doubted he was in the woods at all, and they checked the length of the tracks for miles in the direction he'd been seen walking.

Eric Olsen, who ran Saranac Lake's veterans' program, told the police that Paul wouldn't have stayed on the tracks, but would have cut off at the first trail he'd seen. "Being a 'man of action,'" Olsen explained, "McKay would try to move through his depression. He would not stop until he was out of the manic mood or otherwise incapacitated." He would go to extremes, Olsen elaborated. He told the searchers to look up high.

Canberra, to Paul, felt like exile. He was half a world away from his post and the duties he'd been trained to carry out, and his superiors had ordered him into treatment. If, as Eric Olsen says, soldiers returning from combat need to find their way back into the world, to re-gain a lost sense of purpose, Paul applied himself to the task as diligently as any training regimen he'd ever taken on.

He returned to his military histories and marked them up anew, noting passages about the last battalion to leave Vietnam, and how commanders devised busywork to keep the soldiers' spirits high. He spent the year filling his non-work hours with a wide array of new pursuits: a local Freemasons' lodge, a church, an amateur Australian rules football team, a hip-hop dance group, and a Canberra unit of the State Emergency Services—Australia's large national network of volunteer emergency, natural disaster, and rescue organizations.

Simultaneously, he began to shut out almost all his army friends. He stopped returning their texts and calls, and when he encountered them in public, he sometimes pretended not to see them. He didn't want to be on his medication, and he didn't want anyone knowing or talking about his PTSD, said his ex-girlfriend. "He knew people knew, so he cut them out."

It's hard to say whether Paul's fears of involuntary discharge were rational. Some Australian service members believe that, at most, Paul would have remained on downgraded status until he recovered—that Australia invests too much in training each of its soldiers to cavalierly toss them aside. But just as many told another story: of colleagues who'd been discharged after developing PTSD and left to fend for themselves; of poorly trained counselors who bluntly asked whether their patients wanted to kill someone; of Defence psychologists who warned counselees that, if they accepted a PTSD diagnosis, they could "kiss Special Forces goodbye."

In 2011, the Defence Force increased the time allowed for wounded service members' convalescence from one year to two. But Paul, who as a captain had processed other soldiers' discharge paperwork, would have been aware that his two-year anniversary was rolling around.

Somewhere around June 2013, Paul told his mentor that, on doctor's orders, he was off all medications. He was better. But the next month, he started to grow short with his fellow parishioners and began leaving church before the service was over. In August, he sent an email to the parish office, asking to be removed from all rosters. He drifted away from his football team and the SES.

Around the same time, he reached out to a neighboring SES unit, in the Canberra suburb of Queanbeyan, and started training there. Earlier that year, the Queanbeyan SES had become enmeshed in the most expensive search and rescue in SES history. A Canadian Army Reservist named Prabh Srawn, who'd been attending law school in Australia, had gone missing in the Snowy Mountains near Canberra. During school break, he'd gone hiking on a popular trail when an early blizzard hit, bringing nearly instantaneous whiteout conditions. Although 40 SES staff and volunteers searched for weeks, Srawn was nowhere to be found. As June arrived, and winter weather threatened to make travel in the Snowies impossible, the search was suspended.

Paul befriended the alpine coordinator of Queanbeyan SES, fellow veteran Adrien Hopkins, and inquired about the search, which was set to resume once the snows melted in November. When Paul went missing, Hopkins wondered whether he had been inspired by Srawn's story—enchanted by the idea of disappearing into the snow and never being found.

In 2012, the U.S. Department of Veterans Affairs released a much-debated report estimating that between 18 and 22 veterans were taking their own lives each day. That's almost one suicide per hour. And a 2015 study found that suicide rates were nearly twice as high for those who left the military, compared to those who remained in, and nearly triple for those who left under less-than-honorable conditions. According to Michael David Rudd, co-founder of the National Center for Veterans Studies and president of the University of Memphis, the majority of military suicides haven't been among direct combat veterans, but are often instead people who were vicariously exposed to the trauma of combat—like staff who worked in mortuaries—or just those who fell victim to the intense stresses of wartime. Some research indicates that personality characteristics like perfectionism and overachievement are linked to higher rates of depression and anxiety, and thereby to a higher risk of suicide, but Rudd also points to the obvious fact of the military's tough-it-out, masculine culture, which discourages seeking help.

PTSD is one of the most prominent predictors of suicide and attempted suicide among soldiers. Although PTSD rates range widely, data from a September 2015 VA report showed that nearly 32 percent of Iraq and Afghanistan war veterans who used VA health services between 2001 and 2015 were diagnosed with PTSD. And a 2011 poll of recent veterans revealed that many more who had never been diagnosed believed they suffered from PTSD. The modern wars were partly to blame. Deployments were longer and more frequent. Veterans reported greater strains in re-integrating into civilian life. An overwhelming majority of active and former military members felt the public had no clue what they went through.

Researchers went into overdrive attempting to identify factors for risk and resiliency. There were many, from previous mental illness and substance abuse to enlistment age, level of education, and social and family support. A 2010 study of Nepalese child soldiers found that what happens after a soldier returns home can be more important than the underlying trauma: Those who feel welcomed tend to thrive, while those who feel rejected are more prone to developing PTSD. Another study in 2012, concerning Danish soldiers who deployed to Afghanistan, suggested previous trauma was one of the most significant risk factors. "There's not even a close second to that" in terms of vulnerability, Rudd said. When you've been traumatized once, it's easier to be wounded again.

Shortly after the two-year anniversary of Bloody Saturday, in November 2013, Paul met up with his ex-girlfriend and tried to reconcile things. She was shocked by his condition. He'd shaved his head and was alarmingly thin. He read a list of apologies for being a lousy boyfriend and asked repeatedly whether they could get back together. In December, as most of the Defence Force was preparing to go on leave, Paul texted her to ask if he could accompany her on her upcoming vacation to Turkey. She was in a new relationship and said it wouldn't be right.

Paul then called Peter O'Leary and asked if he'd join him on a spontaneous trip to America. They'd go see the best of the U.S.—the battle sites of Gettysburg and Little Bighorn, the monuments in D.C. But Peter and his wife had plans to go to a friend's wedding and couldn't back out.

On Christmas Day, Paul was taken into protective custody by Adelaide authorities, after police received a call at 2:30 p.m. about a drunken man shouting at people in a park near the McKay family's home. A local constable, Lee Greenwood, arrived and found Paul, dressed in his military uniform but wearing no shoes or socks, and carrying no identification except the insignia on his shirt. He was massively intoxicated and yelling, "I died for you, I died for you." An ambulance was called, and Paul was carried off in a stretcher, alternately crying, retching, and repeating the same words, talking about himself in the past tense, Greenwood remembered, as if he was already dead.

January 15 was Scott van Laer's day off, but he had been mulling over an idea that he just couldn't shake. Maybe Paul hadn't followed the Scarface trail at all. Large-scale searches had been going on for five days, with upwards of 30 volunteers, largely regional veterans, working their way up and around the mountain. An Australian news crew had flown over to film the effort. Every day searchers went out in groups of 10, following assigned paths and marking off search blocks with string. They found surprisingly few clues: one day a sock, another the remains of a campfire, neither convincingly tied to Paul.

(Illustration: Corey Brickley)

Van Laer knew there was an ice flow on one side of the mountain covered so thickly with evergreens that the searchers in police helicopters wouldn't have been able to see through. He walked out his backyard, up into the woods, and worked his way toward the flow.

"When I started out that day I didn't believe I was going to find him. I thought there was no chance," he recalls. At first he thought that he'd come upon an illegal hunting camp. "And then I got closer and I thought, 'Oh. We've ended the search.'"

Paul's body was lying on the ground next to a boulder, his hands in his pockets, just beside a shallow trench. His belongings were tucked between the rocks, and the plastic shovel lay nearby.

Staff at the complex in Ray Brook had become accustomed to the sound of helicopters moving back and forth over the mountain. But that afternoon, as they looked out their windows and saw a helicopter return bearing a litter, they knew Paul McKay had been found.

The local coroner determined Paul's death was a suicide, due to intentional hypothermia and emaciation. Saranac Lake Mayor Clyde Rabideau announced the news on Facebook that afternoon. Within hours, the post was liked and shared thousands of times. Locals wrote to express their sorrow, to say how they'd felt that they'd somehow known Paul. Australians commented in droves, thanking Saranac Lake for treating a stranger as one of their own. Others wrote with more bitterness: "RIP Paul, another soldier let down by the system."

A State Police escort was arranged to accompany Paul's body to New York City, from where he was flown home. At 7:30 a.m. on the frigid morning of January 23, with thermometers hovering around 20 below, some two dozen locals lined the streets of Saranac Lake and Ray Brook to see Paul off.

The reception in Australia wasn't as warm. There was no ceremony to welcome Paul home, as would have been the case if he'd died in combat. His name wouldn't be engraved outside the Hall of Memory at Canberra's Australian War Memorial so that visiting children could participate in the ritual of placing a plastic poppy alongside it.

At the funeral reception, Paul's friends speculated over why he'd gone where he had. To his mother, a devout Anglican, it seemed that Paul was on a religious quest, like the biblical wise men, following a star he didn't quite understand. Other friends thought it must have been the proximity of the 10th Mountain Division, or just the appeal of a completely foreign environment. Or maybe something as simple as a postcard he'd once seen or something he'd read in a book.

What stuck with van Laer was the unmistakable impression that Paul had wanted someone to look for him, and one day to be found. "But why would he want there to be a search?" he asked. To Australian veterans, the answer was obvious. Since 2000, estimates suggest that nearly three times as many active Australian soldiers and nearly five times as many veterans have committed suicide as have died fighting in Afghanistan. But before Paul, almost none had been nationally recognized.

"He could have easily died in Australia," said Troy Rodgers, a veterans' assistance worker. "But if he committed suicide here, no one would ever know about it. Obviously he had a clear thought in his mind that he's going to do it and do it in a way that will make some noise."

John Bale, CEO and co-founder of Soldier On, a national veterans' support group based in Canberra, agreed. Before Paul's death there had been a near blackout on news of the growing number of soldier suicides in Australia. It wasn't so much that Paul changed the conversation, said Bale: "It didn't exist in conversations before this. It does now."

On April 25, 2014, Saranac Lake declared its first-ever observation of ANZAC Day—Australia's annual commemoration of veterans—and a procession of local and Australian authorities climbed up Scarface Mountain to where the forest rangers had constructed a small stone cairn and a wooden cross, to which one of them tied a poppy while another poured a can of Foster's on the ground. Paul's parents came that summer, bringing Paul's ashes to the mountain and scattering them above the cairn.

Andrew Belkin and Laura Flint came to Saranac Lake as well. Andrew wanted to say his personal thanks to the authorities who'd searched for Paul that winter. He and Laura got a room on the shores of Lake Flower, directly across from the Best Western where Paul had stayed. Early on a Monday, still groggy from jet lag, Andrew got up and walked out of town. Armed with a topographical map that my brother had printed for him, he traced, as closely as he could, what he determined to have been Paul's route: down the road, up the tracks, onto the trail. An hour later, Laura and I drove to the main trailhead and followed him to the summit that Paul never reached. Trees blocked the view, and the scent of blueberries lingered in the air.

We worked our way back down to where the rangers' blue plastic locator ribbons still hung from the trees, then cut off the trail, walking for 10 minutes over the spongy forest floor, up to the quiet shoulder, where Andrew went in alone. "I wanted to see where Paul went," Andrew said. He isn't a spiritual guy, but people had told him he'd find Paul on the mountain, and finally understand why he'd gone. "But at the end of the day, for me," he said, "it was just another mountain."

Why Paul did what he did will likely remain a mystery. Perhaps his unforgiving drive and perfectionism set him up to come apart in the face of the horrors he saw in Afghanistan. Perhaps he needed more help than he got re-integrating into society after serving in a war zone. Perhaps it's wrong for a civilian like me to even speculate. What does seem clear from the clues he left behind is that Paul struggled to operate under the weight of his experiences. Those who knew him best described their sense of no longer really knowing him.

Andrew Belkin, after his visit to Scarface, sent a note to Paul's parents along with a photo of the cross and the cairn in the shadow of the boulder. "It was a very quiet spot," he wrote. "Sadly I didn't find Paul there. I think I lost him a long time ago."

"He disappeared like he had disappeared off the face of the Earth," recalled Reverend Brian Douglas, Paul's pastor back in Canberra. "But really, he had disappeared before he actually left. He had gone to another place emotionally, which you couldn't reach."

Long before he ever set foot in Saranac Lake, Paul McKay was already gone.

Lead Photo: (Illustration: Corey Brickley)

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