EPISODE 9 -- Marilyn Koolstra embarks on an unexpected pilgrimage to the place where her husband, Eric Robinson, lost his life in the Uinta Mountains. The journey into the wilderness tests her physical, mental and emotional limits. But Marilyn doesn’t travel alone. Friendships forged through tragedy help carry her through to the end.

EPISODE 8 -- Eric Robinson took 77 photographs on his last hike. Those images, recovered with Eric’s remains in 2016, tell the story of what he experienced on the Uinta Highline Trail. They also contain clues about why Eric diverted from the trail in his final hours. Dave Cawley follows those breadcrumbs to the brink in search of answers.

EPISODE 7 -- Marilyn Koolstra returns home to Australia without any answers about what happened to her missing husband, Eric Robinson. As months turn to years, she’s forced to accept the awful reality of his death at some unknown place in the Uinta Mountains. But an accidental discovery in those mountains will one day stun everyone involved in the search for Eric.

EPISODE 6 -- The last glimmers of hope fade as the search for Eric Robinson enters its final stage. The Duchesne County sheriff, running out of time and money, makes one last push to find him. Searchers brave the weather and the wilderness in the hopes of sending Eric’s wife, Marilyn Koolstra, home to Australia with answers about her husband’s fate.

EPISODE 5 -- As news coverage of the search for Eric Robinson spreads, a Boy Scout leader tells of spotting Eric far off the Uinta Highline Trail. This encounter along Yellowstone Creek raises questions about Eric’s state of mind and expands the search area to include an even greater swath of High Uintas Wilderness. Was Eric lost? Uinta Triangle host Dave Cawley poses a new theory.

EPISODE 4 -- The wife of missing trekker Eric Robinson flies halfway around the world, from Australia to Utah, in search of her husband. A rural sheriff struggles to organize an effective rescue across the vast expanse of the High Uintas Wilderness Area. An unlikely meeting along the Uinta Highline Trail brings Eric’s friends into contact with some important new allies at Dead Horse Pass.

EPISODE 3 -- Eric Robinson doesn’t show up at the end of the Uinta Highline Trail. Eric’s friend reports him missing, kicking off a search-and-rescue mission. Marilyn Koolstra, meanwhile, feels powerless to help her husband from half a world away. Uinta Triangle host Dave Cawley sets off on his own solo hike, looking for clues about Eric’s disappearance.

EPISODE 2 -- Eric Robinson forges a new friendship on the John Muir Trail, while an old friendship frays under stresses of the trail. From the High Sierra to the Himalaya, Eric’s aspirations in the outdoors continue to grow. His wife, Marilyn Koolstra, accompanies Eric on some of his adventures. But a rift emerges when Eric insists on going out alone after a few close calls with death in the mountains.

EPISODE 1 -- Eric Robinson wanted to hike the world’s greatest trails. He was happiest when spending weeks in the wild, and he often went out alone. Eric’s wife, Marilyn Koolstra, supported him in this goal. But the situation changed when Eric went missing on a solo trek to the Cascade Saddle in New Zealand. This episode traces the origins of Eric Robinson’s passion for trekking, the past traumas he tried to soothe in nature, and the midlife romance that brought Marilyn into his life.

An Aussie who loves hiking solo goes missing in the rugged mountains of the American West. Dave Cawley, the investigator behind the podcast COLD, heads into the wild to answer the question: What happened to Eric Robinson?