It’s a blistering July afternoon in the quiet neighborhood of El Sereno, the oldest community in Los Angeles and the unassuming blue-collar backdrop for AMC’s “Fear the Walking Dead,” the new companion series to the highest-rated drama on television. A herd of disheveled extras shuffles past; men, women and children corralled into ragtag formation, the hum of their voices echoing off the abandoned houses lining the cul-de-sac.

But unlike in “The Walking Dead,” there’s not a zombie in sight amid the crowd. These people are decidedly human, their costumes comprised of face masks, bathrobes, pajamas and ponchos as they gather around a military-issue Humvee, seeking guidance from the Army, the only higher power that’s answering the phone at the onset of an unidentified pandemic.

In “The Walking Dead,” civilization has already crumbled, and the characters that inhabit it are hardened by loss — but in the six-episode prequel “Fear,” which will span roughly the first three weeks of the outbreak, we enter a world that’s yet on the brink of collapse.

“Because we weren’t starting with the zombie horde, one of the things that’s important is feeling a sense of anxiety — apprehension of what’s to come,” says showrunner Dave Erickson. “There’s something wonderful about seeing the landscape of East Los Angeles, and the hills and the freeways and the houses layered one on top of another, yet having the audience know full well what’s coming down the pike. Every time you look out into that world, you know that all those people are about to die.”

The companion series is playing on the audience’s familiarity with horror tropes to build tension, even as its characters struggle to comprehend what they’re facing.

“What I wanted to explore was this idea of what makes us human,” says exec producer Adam Davidson, who also directed the first three episodes. “In the face of such a catastrophe, do we rise to the best of ourselves as human beings, or do we sink to the lowest? What you have to ask is: Who do you need to be more afraid of, the zombies or the other human beings around you?”

That AMC would look to spin off its biggest hit isn’t much of a shocker. Its monster ratings dwarf most broadcast series in the 18-49 demo. The only question, then, was the story: What plot could drive the new show?

AMC president Charlie Collier says wherever he’s traveled, he’s been asked one question: What’s going on in other parts of the globe during this apocalypse? “The moment (‘Walking Dead’ creator) Robert Kirkman leaned in and said he had more story to tell, and he thought he could envision a world with all the rules of ‘The Walking Dead,’ with all the gravitas of the world of ‘The Walking Dead,’ obviously we were very intrigued,” says Collier.

Transplanting those dynamics from Atlanta to Los Angeles was key to give the show a compelling, different look, as was bringing in a new creative team (although the show still counts “Walking Dead” mainstays Gale Anne Hurd, David Alpert and Greg Nicotero among its producers). Much like the protagonists in “Fear,” Erickson and Davidson are newcomers to the ethos of “The Walking Dead,” which Erickson admits was by design. “We always had a very specific tone and vision in our heads, but in bringing in people who were coming to it fresh, no one was trying to second guess what we were doing in comparison to the original, which I think was helpful,” he says.

That unsullied perspective also informed the overall vision for the show. Recalls Collier, “The day I sat down with Dave Erickson, we didn’t talk about walkers and zombies for a long while,” he says. “The first thing he wanted to talk about was what it would be like to be a parent in a broken family during the zombie apocalypse, and what would it be like if you were not necessarily a cop or a person who’s built to survive in this world — if you were a guidance counselor or a teacher, and you had to learn who you were going to be to survive and thrive.”

Instead of leaping straight to the undead, the series takes the time to establish the complicated dynamics among its core characters — new couple Travis Manawa (Cliff Curtis) and Madison Clark (Kim Dickens); her teenage children, Nick (Frank Dillane) and Alicia (Alycia Debnam-Carey); and his ex-wife, Liza (Elizabeth Rodriguez) and son Christopher (Lorenzo James Henrie).

“Even though we start from a very specific family-drama place, the difficulties and conflicts they have will be quickly exacerbated by the apocalypse,” Erickson says. “If the audience is coming to the show looking forward to seeing walkers, they’re not going to be disappointed. But it’s at a slightly different pace than the original show, and it also allows the characters to actually process what it would be like to have to put somebody down.”

That moral dilemma proved to be one of the most appealing aspects of the show to the cast, which was eager to explore humanity put to the ultimate test.

“I liked his ordinariness,” Curtis says of high school teacher Travis. “He’s not prepared. He knows who he is in this world, and his identity is really wrapped up in his family life. I know it’s fashionable to be an antihero, but it’s hard to be a good guy and to keep it together … to be a responsible member of your community and to play by the rules. The rules suck a lot of the time; they’re not conducive to you having your way.”

Dickens, no stranger to fan-favorite franchises, with stints on “Deadwood,” “Friday Night Lights” and “Lost,” was initially hesitant to take on the role of guidance counselor Madison, which sounded drastically outside her wheelhouse.

“In the beginning, I thought, ‘I don’t know if I’m right for that kind of show or that genre. I don’t know if they’ll really pick me for that,’” she admits. “Then I read the script and I thought, ‘That’s a really badass character, and that would be really fun to play,’ because she’s completely flawed and complex, and there’s a lot of backstory. There’s this great strength and pragmatism and adaptability to her. I just thought, ‘That’s a real woman.’”

But authenticity is a double-edged sword when the dead are rising. The characters that populate “Fear” aren’t the crossbow-wielding warriors audiences have come to know and love from the original series. And the zombies aren’t the flesh-eating attackers that have already won special-effects mastermind Greg Nicotero two of his three Emmys. “Because the walkers have just turned, and since our people have no history with it, they just see a sick neighbor, sick friend, sick relative,” says Davidson. “They have no idea yet.”

That was part of the appeal of the companion series for Kirkman, says Erickson. It presented “an opportunity to look at certain elements of the show and of the comic that he may not have explored as much as he wanted” — most notably the psychological trauma of inflicting violence on another human being.

“What happens when you’re confronted with a colleague you had coffee with yesterday, and suddenly you’re forced to do something that you never would have considered yourself capable of doing? And then what does that do to you?” he says. “They’re not killing zombies. They’re killing people, and they don’t know if that person could be saved. They don’t know if there’s going to be a broadcast in a few days where they say, ‘Guess what? We figured it out; there’s a cure for this virus!’ ”

For fans of the original series or comics who are waiting for that particular mystery to be solved, don’t expect “Fear” to offer any tidy solutions.

“It’s really not about the why, and it’s not about a cure. That’s never been the intention that Robert had in the comics, and it’s not the intention of the show,” Erickson says. “It’s not an origin story in terms of finding out exactly how the epidemic started, but it is an origin story in seeing how it began to destroy the world.”

While AMC’s “Better Call Saul” managed to deliver on fans’ expectations of predecessor “Breaking Bad,” producers of “Fear” hope the show can also appeal to viewers with no expectations at all. “The marching orders from AMC were always to create something that could survive on its own,” says Erickson.

And in a first for the network, AMC hopes to get the series in front of as many fresh eyeballs as possible by debuting the series around the world simultaneously with its U.S. premiere.

Ultimately, following one of the most popular series on television may seem like a daunting prospect, but for Erickson, the success of “The Walking Dead” actually insulates the companion series. “I’ve never had a conversation with anybody at the network where they’ve said, ‘We really want you to get this (rating),’ or ‘If you get below this, it’s going to be disappointing,’” he says. “There’s not a line that I’m afraid we won’t cross.”