The mystery begins thus: "A young woman in basketball shorts and a hoodie — she's the same age as Google — walks down the street towards a bookstore." That's how creators Zal Batmanglij and Brit Marling describe stage directions that introduce Darby Hart (Emma Corrin), protagonist of the FX limited series "A Murder at the End of the World." Darby quietly waits in the back of a small crowd until she's summoned to the lectern to read from her own true-crime memoir.

Enter the next great TV detective.

"Darby knocked us out. We were developing other ideas, but then she just came and wouldn't let go," says Batmanglij. Though he takes issue with the TV label, Batmanglij stresses how the streaming age has freed storytelling from the bonds and structures that would have made this story less interesting to tell: "It's not film, it's not TV, it's some hybrid."

Indeed, the seven-episode "Murder" wears its intellect and social concerns on its sleeve in ways that would have made the gatekeepers of old slam their portals shut. The climate crisis, for instance, is woven into the fabric of a murder mystery; the series' depiction of sex and sexuality is considerably more adult (and realistic) than you're likely to find on a broadcast procedural; and its very structure gleefully violates rule after rule of how it's been done before.

And its protagonist — thoughtful but punkish-looking, pink-haired Darby, a 24-year-old amateur sleuth who is low-key the smartest person in the room — doesn't fit the template of the standard whodunit heroine. But here she is, an unlikely attendee at a summit of great thinkers engineered by a tech titan named Andy Ronson (Clive Owen) and his wife, Lee Andersen (Marling), a legendary hacker who has retreated from public life. The assembled accomplished geniuses include the first woman to walk on the moon (Alice Braga), a Chinese builder of "smart cities" (Joan Chen), an omnivorous venture capitalist (Raúl Esparza) and a Banksy-like artist-activist (Harris Dickinson), among others.

So what is Darby, this young, tech-savvy, first-time author doing among these heavy hitters? Marling says she and Batmanglij showed the series to a friend familiar with the milieu, and he said, "A person who looks like that on these technology retreats is usually there for sex."

The task of making this slight creature a formidable force was the very thing that drew them to it. As Darby says, "No one sees a 24-year-old girl coming."

The pair's catalog of screenplays, teleplays and directorial efforts, and Marling's performances, are marked by a striving, searching intelligence. Yet after Marling broke into the industry thanks to a succession of well-received films at Sundance, she says the roles she was offered were neatly plucked from the "girlfriend or wife" or "bikini girl" ... or "dead girl" lockbox. The Darby Harts of the world "were simply not on offer." So crafting a young woman who is underestimated, even dismissed, at this highfalutin' meeting of minds came from experience. Although, as countless lesser detective stories prove, it's difficult to convey that a character really is the smartest person in most rooms.

"Brit says the only thing you can't act is brilliance," says Batmanglij.

Establishing that Darby's deductions aren't magic, but entirely earned, was a top priority. "We spent a lot of time doing deep research to try to think of the proofs we could build that would get you on board," says Marling.

What the others at the retreat don't know about Darby is that she grew up as the coroner's daughter and was on crime scenes from the time she was 8, Marling says. "She found amateur sleuthing when she was in her teens. She's logged her 10,000 hours on the internet, solving cold cases."

Thus the series simultaneously unspools two mysteries: the titular murder in the show's present and a string of crimes in the past, as teen Darby tracks a serial killer while falling in love with her sleuthing partner. We see her dogged legwork; we see her flashes of inspiration. That origin story is introduced in the show's opening moments, as present-day Darby reads from her true-crime chronicle of the experience — beginning at its end.

"With all our internalized prejudices, we don't necessarily believe she has a right to be there," Marling says. "In order to build [that] proof, you have to braid it with her past at the same time, so you're using her origin story to (convince) the audience, 'No, this young woman doesn't have to be the victim at the scene of the crime. She can be the person solving it.'"

As a narrative device, that braid keeps viewers juggling — and invested in — two timelines, but also provides the pieces of proof that build the larger argument: Darby's intelligence is real. So it's all the more frustrating when, in the present, she is dismissed and obstructed.

"The scene where Darby interviews the other guests, which is a classic trope of the genre and would usually happen at maybe minute 30 in a movie or the second chapter of a series — every time we tried to write that scene, it did not feel real. It felt like Nancy Drew or a little tongue-in-cheek and pushed and not credible," Marling says. "It wasn't until we had done five hours of storytelling with Darby that she could interrogate the guests, but only if Andy was sitting next to her."

Batmanglij adds, "The generation below us has grown up completely in the world of technology.

"We were fascinated by (that dynamic) that allows this generation to go toe-to-toe with a billionaire who has all the power and intelligence and all this stuff," he says. "We wanted to tell a story of how this generation can hold the other generations to task."

That dynamic is also subtly expressed as one of the series' themes: the climate crisis. Big ideas permeate the pair's work, including cult-like devotion ("Sound of My Voice"), environmentalism in the extreme ("The East") and existence beyond death ("The OA"). The title of the new series is a double-entendre: The retreat takes place in Iceland, which some would consider the end of the world; and the climate crisis — the looming end of the world.

As one character in the series, a gloomy alcoholic climate activist, says, "Climatologists who've been in the game a long time know how it's going to end ... and sooner than you think."

When it comes to climate change, "it's not that we don't have the answers," Marling says. "We all know what we need to do; we just seem unable to do it. A lot of activists talk about reaching a place of burnout, where you've been at it for so long and the resistance is so intense — and growing more intense — that you can be deflated."

Despite the darkness of that scene, Marling says she kept thinking about how there is still hope for change.

"It may be a sharp-edged hope, hope like a razor blade, but you can use a razor blade to cut a hole in a box you're stuck in and crawl out," she says.