Lankford recounts how, in 1926, Catherine Montgomery and Joseph Hazard proposed the creation of a wilderness footpath along the Pacific Coast, inspired by the developing Appalachian Trail in the East. In 1932, Boy Scout leader Clinton C. Clarke, a wealthy Harvard graduate, began designing the trail and formed the Pacific Crest Trail System Conference to unite government agencies and outdoor organizations. The National Trails System Act of 1968 officially designated the Pacific Crest Trail (PCT) as one of America’s national scenic trails. 

In 1970, Eric Ryback completed the first recorded thru-hike and published a bestselling memoir. The trail remained secondary to the Appalachian Trail until 2012, when Cheryl Strayed’s memoir Wild increased interest. After the 2014 film adaptation, thru-hike permit requests surged from 1,879 in 2013 to 7,888 in 2019, forcing the Pacific Crest Trail Association (PCTA) to implement a permit system. Interest brought inexperienced hikers seeking personal redemption, diverging from Clarke’s vision of a primitive route for experienced hikers.

Today, fewer than 12% of aspiring thru-hikers complete the 2,650-mile trail. The first person to disappear from the trail corridor was Louise Teagarden, last seen on December 17, 1959. In 1991, hikers discovered her remains in a cave two miles from the trail. Since then, all other missing hikers had been found, until Chris Sylvia disappeared.

In early 2015, 28-year-old Chris Sylvia was living in Vista, California, with his best friend Min Kim and their roommate Elizabeth Henle. After a series of personal and professional challenges, Chris spent his days partying while Min struggled to cover rent. Tensions mounted in the apartment. Min suggested Chris hike the Pacific Crest Trail alone to clear his head. On February 12, Chris began hiking south from the Anza Trailhead, borrowing gear from Min and a flip phone from Elizabeth. As a romantic gesture, he left Elizabeth his “lucky” compass with a note promising to return for it. He planned to reach the Mexican border 152 miles away, possibly returning north.

After four days, Chris called Min asking to be picked up at a Buddhist monastery the next day. The pair argued, but Min agreed. When Min drove to the monastery, he found no sign of Chris. After waiting a few hours, she returned to work, assuming Chris had continued. After a week had passed and all calls to Chris’s phone went unanswered, Min reported his friend missing.

On February 20, 2015, hiker Eric Trockman discovered abandoned gear beside the trail near Chihuahua Valley Road and photographed it. Five days later, seeing a Facebook post about Chris Sylvia’s disappearance, Trockman reported his finding. No one interviewed him until Lankford called two years later.

In February 2017, while following the Chris Sylvia case, Lankford reads a Reddit post by Chris’s brother, Joshua, who had hoped the television show would investigate. Knowing the show is cancelled, Lankford contacts the family and promises to help. On November 6, 2017, she meets Trockman, and they visit the gear site, determining it was a good spot for hitchhiking but not for camping. They found no cell service nearby.

A short hike led them to Mike’s Place, a hiker hostel with a mixed reputation. The caretaker, Josh McCoy, is initially hostile and evasive when Lankford questions him. He claims that Chris never reached the hostel and shows her a trail register starting after Chris’s disappearance, although Lankford finds pages from an earlier register.

After consulting her husband, Kent Delbon, a federal law enforcement agent, Lankford returns the next day with food—a gesture of goodwill known as “trail magic.” McCoy apologizes and explains that he feared frightening other hikers. He reveals his theory: Chris may have encountered violent marijuana growers operating in the area. Lankford searches the terrain and finds the vegetation too dense to conceal a body without leaving evidence.

Back in her cabin, Lankford researches Kris Fowler and David O’Sullivan, noting similarities in their cases.

In October 2016, 34-year-old Kris Fowler neared the Canadian border after hiking more than 2,000 miles of the PCT. From Beavercreek, Ohio, Kris was recently divorced and had left his corporate marketing career for construction work. Seeking adventure, he began his thru-hike on May 8, 2016, with friend Colin Hurley, though they separated to hike at their own paces.

Kris had earned the trail name “Sherpa” in Idyllwild, California, after helping fellow hikers. A photograph showed him carrying Wanderer, Sterling Hayden’s memoir about escaping modern society’s constraints, mirroring Kris’s own disillusionment with corporate life. On October 5, he had joked to other hikers that being the last to reach Canada would be a win, reflecting his noncompetitive, meditative approach.

With approximately 352 miles remaining to the Northern Terminus, Kris had faced the psychological challenge all thru-hikers confront near the trail’s end: Reintegrating into society after months in the wilderness. Lankford suggests that questions about his future weighed on Kris. On October 12, 2016, Kris entered the “cold, dreary woods” at White Pass (32), Washington, and was never seen again.

Six months after Kris Fowler’s disappearance, 25-year-old David O’Sullivan from Cork, Ireland, began his northbound PCT thru-hike on March 22. A studious graduate, David was inspired to hike by Cheryl Strayed’s Wild. He still lived with his parents.

Arriving at Paradise Valley Café on April 3, 2017, David met hiker Daniel “Beta” Winsor. Their discussion confirmed that David was an inexperienced hiker on a steep learning curve. David and Beta discussed trail conditions ahead. Recent snowfall had made the San Jacinto Mountains dangerous. Unlike the purist Beta, who refused to skip sections, David planned to bypass the High Sierra and return when conditions improved. Beta struggled to hitchhike back to the trail but saw David pass in a silver car, inspiring the trail name “Lucky Dave.” Three days later, David sent a final email to his family. It was the last time they would hear from him.

Lankford compares her own 1999 Appalachian Trail thru-hike to the experiences of the missing men, noting how smartphone technology has transformed both hiking culture and search efforts. She explains “Bring Kris Fowler/Sherpa Home,” a Facebook group led by his stepmother Sally Fowler, and run by volunteer Cathy Tarr. In October 2017, Cathy announces she will pause her Washington search for Fowler to help David O’Sullivan’s family in California.

Struck by similarities—Chris and David disappeared only 52 miles apart—Lankford contacts Cathy. They meet for dinner in Hemet, where Cathy, a retired Walgreens manager with no search-and-rescue (SAR) experience, explains that she felt compelled to help when she realized no authorities were looking for David. Lankford agrees to oversee Cathy’s first major search operation.

The next day, they meet David’s parents, Con and Carmel, with a retired homicide detective in Idyllwild. The O’Sullivans described official mishandling of David’s case: delays in determining jurisdiction, a rude and dismissive PCTA representative, and a four-month gap before Riverside County officially opened an investigation in late July. Despite efforts by the volunteer Riverside Mountain Rescue Unit, searchers had found only an unrelated purple sleeping bag.

Lankford conducts an informal interview, learning that David was conscientious, disciplined, and sympathetic to underdogs. At the library where David sent his last email, they discover a world map where thru-hikers place stickers marking their origins. A red dot on Cork moves Carmel to tears.

Lankford battles San Diego County bureaucracy to obtain Chris Sylvia’s missing person report, until finally Joshua Sylvia receives a heavily redacted three-page document lacking a crucial itemized list of recovered gear, essential for leads. Lankford notes she would later obtain a vital clue the authorities had missed, connected to the compass Chris had intentionally left behind.