“Was Dr. Ritter, With His Steel Teeth, Poisoned in Paradise? Was ‘Baroness Eloise,’ Known as ‘Crazy Panties,’ Who Ruled the Island With a Gun and Love, Murdered by One of Her Love Slaves After She Had Driven the Other to His Death? And Why is Frau Ritter Going Back to What She Once Called ‘Hell’s Volcano?’ – the Mystery of the Galapagos Island Which Germany Covets, to Be Solved At Last?”

This florid passage from a tabloid newspaper caught the eye of the author Abbott Kahler decades after it was published in 1941. “Basically it was the equivalent of a record scratch,” she recalls. “I was thinking: what the hell is the story?”

The answer revolves around a group of Europeans from the 1930s who attempted to start anew on the remote island of Floreana, only to encounter the human frailties they hoped to escape: chaos, blackmail, betrayal, disappearances and murder. The enduring mystery of what exactly happened is known as “the Galápagos Affair”.

Kahler became so obsessed that she wrote a book about it called Eden Undone. And she is not alone. Ron Howard, the Oscar-winning film director, learned about the story when he saw some photos at a museum in the Galápagos. This led him to make Eden, a movie starring Jude Law, Ana de Armas, Sydney Sweeney and Vanessa Kirby released on Friday.

Kahler understands the Hollywood potential. “I’ve made a career of writing about stranger-than-fiction true stories and this is by far the strangest one I’ve ever come across,” she adds. “Just aside from the incredible cast of characters, it has timeless themes that still resonate today.”

Indeed, Howard’s film opens with the blunt statement: “Fascism is spreading.” Germany between the wars faced mass poverty, social unrest and extremism that gave rise to the Nazi party. Some people looked for a way out and a new way of living free from societal constraints.

The Galápagos Islands off the coast of Ecuador, famed for scientist Charles Darwin’s expedition, were thought of as the last great unspoiled territory. Floreana, however, is not everyone’s idea of paradise. It is arid, rough and rugged and had historically served as a stopping point for pirates collecting tortoises for food.

A German doctor called Friedrich Ritter left his wife and travelled to Floreana with a married woman, Dore Strauch. The austere, misanthropic Ritter was driven by Nietzschean ideals and a desire to escape civilisation and come up with a radical philosophy to save humanity from itself.

Ritter was a strict vegetarian and extracted all his teeth and replaced them with steel dentures before leaving. He showed little sympathy to Strauch, his former patient, who was suffering from multiple sclerosis.

A visiting US scientific party were fascinated by this “modern day Adam and Eve” and effectively publicised their lives for the press back home, attracting more utopia-seekers such as Heinz Wittmer, a veteran of the first world war, with his second wife Margret and young son. Margret was pregnant and gave birth to the first child officially born on the island.

Tensions between the two families were further exacerbated when Eloise Bosquet de Wagner Wehrhorn, an adventuress who called herself the Baroness, arrived with her two lovers, Rudolf Lorenz and Robert Phillipson. The Baroness’s flamboyant lifestyle, declarations of being “empress of Floreana” and plans for a luxury hotel directly clashed with the other settlers’ visions.

Kahler says: “She shows up on Floreana in 1932 and immediately starts making enemies. The first thing she does is go to Heinz and Margret Wittmer’s home – they were pretty much the only truly stable people there – and wash her feet in their drinking water. That’s strike one.

“Then she announces that she’s going to turn Floreana into the next Miami: she’s going to build a lavish hotel that’s going to cater to millionaires around the world. All of these other people who had gone there wanted solitude and to be away from civilisation and here she was directly saying that her goal is the opposite and she wants as many visitors as possible. She made it very clear that she felt the island was hers to do whatever she wanted to do with.”

The Baroness’s hedonism was jarringly at odds with Ritter’s asceticism. Kahler writes how the Baroness wielded a riding crop and pearl-handled revolver, staged fights between her lovers and had sex with American tourists. “She pretty much seduced anybody she could. One visitor called her hotel, the Hacienda Paradiso, a ‘festering sex complex’.”

The remote and harsh environment of Floreana intensified the inherent tensions. Food scarcity and the constant struggle for survival amplified mistrust. The community descended into jealousy and animosity. Ritter became increasingly autocratic and the Wittmers struggled to survive amid the discord.

Kahler observes: “It’s people left to their own devices away from the rules of civilisation. What kind of rules will they concoct? Or what kind of lawlessness do they concoct?”

In March 1934 the Baroness and Phillipson mysteriously vanished. While the Wittmers claimed they left for Tahiti, no evidence of their departure or arrival was ever found, leading to strong suspicions of foul play.

Lorenz, now isolated and fearful, fled Floreana. His decomposed body was found on a nearby deserted island months later, adding another layer to the mystery. Not long after, Ritter died from eating spoiled potted meat, despite his professed vegetarianism. Rumours circulated that Strauch had poisoned him.

Kahler comments: “Two people end up missing and two people end up dead. This is why it reminded me of the Agatha Christie novel And Then There Were None. A bunch of people show up on a remote island and not everybody makes it out alive.”

The lack of definitive proof and conflicting accounts from memoirs by Strauch and Wittmer fuelled the mystery. Strauch returned to Germany, where she died from complications from multiple sclerosis in 1943. Margret Wittmer remained on Floreana until her death in 2000 at the age of 96; her descendants still run a small hotel on the island.

For Kahler, the Galápagos affair taps into a universal human yearning to get off the grid, even if it turned into a grownup version of Lord of the Flies. “Everybody is always dreaming of escaping the drudgery and stress of their daily lives and going somewhere fresh where nobody knows their name and they can leave their problems behind and fashion a brand new utopia for themselves.

“Of course, plenty of examples in history suggest that’s not possible. Wherever you go, there you are – that old adage certainly was true of those settlers in this story. Everybody has a different idea of what utopia is or might be and, when you get a bunch of people together whose visions of utopia clash, what happens? That’s also something that we see time and again throughout history. I’m not surprised it attracted Hollywood.”

The screenplay for Eden was written by Noah Pink, who has previously tackled subjects such as the game Tetris’s unlikely journey from the Soviet Union to global hit. He was introduced to the story by Howard in 2019 and became intrigued by the idea of three factions fleeing Europe with three very different philosophies.

Pink says via Zoom from Toronto, Canada: “I’m boiling it down: Dr Ritter, the purpose of life is pain; Baroness, the purpose of life is pleasure; and the Wittmers, the purpose of life is family. Very simple and when you watch those three philosophies collide, that’s where the fun happens.”

What does he hope audiences will take away from the film? “One is the importance of sticking by your loved ones and, whether that’s chosen family or family, especially in these times when things are seemingly very dark around us, we need to stick together and stick to our community and help each other out.

“It’s also that running away is not the answer because you cannot run away from yourself. If we want to fix things, we have to stay and we have to fix things.”

The intrigue of Floreana also inspired a 2013 documentary, The Galapagos Affair: Satan Came to Eden, directed by Dan Geller and Dayna Goldfine. Goldfine says they were particularly drawn to the “vibrant characters” and the “underlying theme of trying to escape oneself and escape civilisation only to bring your own baggage with you”.

She continues: “It was that perennial humanity’s thirst for paradise and the philosophical issues around it, this notion of what if you actually do follow through on the dream to go off into the sunset and on whatever some paradise island and you get there and other people arrive with their own different notions of paradise.”

• Eden is out in US cinemas now and in the UK and Australia soon