Group Went on Charity Amazon Trek — and Only 1 Finished: Inside the Start of Adventure Gone Wrong

"Expedition From Hell" documents the journey led by special forces veteran Mickey Grosman

A trek for cancer awareness across the Amazon in South America began with two dozen people — but only one finished.

That's the story of the limited docuseries Expedition From Hell: The Lost Tapes, which premieres on Sunday, May 12, on the Discovery Channel and on Max and follows special forces veteran Mickey Grosman as he leads a group of men through the rainforest in an adventure that some involved said went wrong.

The first episode follows the start of the journey as others quickly realize Grosman is not the leader they were expecting.

As participant Kevin Jackson says in the premiere, “He’s a strong guy, don’t get me wrong. But there's gonna be a strong guy with no team if he keeps pushing everybody else the way he's pushing. I don't think there's one happy person here besides Mickey.”

<p>Warner Bros. Discovery</p> Mickey Grosman and the crew hiking in "Expedition from Hell: The Lost Tapes."

Warner Bros. Discovery

Mickey Grosman and the crew hiking in "Expedition from Hell: The Lost Tapes."

Grosman, who survived cancer, promoted the trip as a way to bring attention to and fund cancer research. Once a member of the Israel Defense Force, Grosman decided to form a team to make the 5,000-mile expedition.

“Nothing like it was ever documented before, where somebody ... walks from one side of the Amazon and makes it to the other end in one piece [without] like losing his leg or losing his life,” one of the documentary-makers said in Expedition.

The premiere shows the team starting their adventure off in Ecuador by picking up local guides native to the area. Grosman said to follow him.

“I'm not playing games here; I will continue without you,” he said.

Related: Hunter Lost in Amazon Jungle for 31 Days Survived by Eating Worms, Collecting Rainwater in His Boots

Robert Finlay, another participant featured in the first episode, is a former member of the military who had a passion for survival expeditions.

He said in the series that he “rearranged [his] life” to join the journey.

“A leader is simply a guy who facilitates the accomplishment of the mission with his team,” Finlay told cameras as the group got off to a rocky start, with people being left behind and what he called unnecessary river crossings putting some of the explorers at risk.

“There's a team here. We should be making people stronger, period," he said.

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Finlay was not afraid to speak up — but throughout the first episode, he was met with a hostile response from Grosman.

“I do my expedition in my way,” the leader said constantly.

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Jackson, who had been a part of survival camps before, found that Grosman "carries himself in a way that you kind of believe him,” he said. But that feeling changed.

As the trek continued, when asked if he still believed in Grosman, Jackson replied, “No,” before adding, “His style is, ‘It’s either my way or the highway.’ ”

Jackson also joined the group a couple weeks into the journey, so he said he fell behind because he had less time to acclimate.

Noting that the others would often move on without him, Finlay said that was a failure on Grosman’s part.

“[His] leadership was horribly lacking,” Finlay said.

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Though the hike was advertised as a journey of exploration and bonding, Jackson described it as “military style” and eventually felt discouraged because of what he called Grosman's lack of support.

“It’s more like breaking down and less of an adventure,” he said.

When Grosman began criticizing the way the guides prioritized safety and rest, he fired them. That was when the team began to see Grosman's anger — and what they felt was his mistreatment.

“He was mad at me for catching him making a mistake,” Finlay said.

“You shut up like a fish, but behind my back you start to manipulate my employees,” Grosman told Finlay, who called Grosman "tyrant-like."

Grosman then kicked him off the expedition.

<p>Warner Bros. Discovery</p> The groups crosses rapids in "Expedition from Hell: The Lost Tapes."

Warner Bros. Discovery

The groups crosses rapids in "Expedition from Hell: The Lost Tapes."

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Toward the end of the episode, Alexander Hernandez took Finlay's spot. Quickly, he realized what he had gotten himself into.

“I didn't think Mickey was taking a route because it was better; I thought Mickey was taking a route because it was harder,” Hernandez said.

At the end of the episode, the group got lost in the mountains for more than seven hours after Grosman and a local he enlisted led them across a treacherous “short cut.”

“It’s not life or death yet," Jackson confessed, "but it’s pretty close."

Expedition From Hell: The Lost Tapes premieres May 12 at 10 p.m. ET on the Discovery Channel and on Max.

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