(USA TODAY) -- As the scene opens, a man tends his vegetable garden, listening to country music on his earbuds and enjoying the sunny day.
This is The Walking Dead? Yes, it is. Just feet away from the lawman-turned-farmer Rick Grimes (Andrew Lincoln), a crowd of walkers - the term for flesh-eating zombies on the hit AMC drama - push against a chain-link fence, a reminder of ever-present danger in this post-apocalyptic world.
And, since this is The Walking Dead, the bucolic scenes in the survivors' prison compound at the opening of Season 4 (Sunday, 9 p.m. ET/PT) are fleeting. Threats from inside and out will soon arrive.
"You think it's all nice and cuddly like The Waltons," says Lincoln of the tranquil opening. "Oh, no. Not with Rick Grimes. ... It's not going to last too long. It only goes from bad to worse."
Much has changed in the six months since Rick's small band fought off the forces of The Governor (David Morrissey), a menacing man who disappeared at the end of last season, but not for long. The desolate prison is now a bustling community, with survivors from The Governor's Woodbury and others joining the group.
Rick has backed away from his leadership role, trading his gun for a hoe, choosing to cultivate rather than kill. His main concerns are his children, although coming threats may demand his attention.
"I think the season can be summed up in a question: Can we ever come back from the things we've perpetrated, the brutality of the things we've seen? Can we ever love again, live again, be the people we once were in this new hell?" Lincoln says. "And I think that question is interwoven into a lot of characters' story arcs this season."
Glenn (Steven Yeun) and Maggie (Lauren Cohan) are happy together, although divided on how to approach life in such a hazardous and uncertain world. Carol (Melissa McBride), once a meek victim, has developed a harder shell, teaching the community's children about self-defense. She and Daryl (Norman Reedus), once an outsider, have grown closer and are members of the community's leadership council.
Carl (Chandler Riggs), whose killing of a surrendering youth from The Governor's assault squad caused Rick to change his stripes, seems to have regained some balance. And loner Michonne (Danai Gurira) accepts and has been accepted by the tight-knit community even as she remembers The Governor's role in the death of her friend Andrea (Laurie Holden).
His whereabouts "are a loose end that's untied. It's even beyond vengeance. It's about what's smart. Is it smart for this guy to be out there and we don't know where he is?" Gurira says. "For (Michonne), it's not even just about vengeance,. It's also strategic, in terms of protecting a community that she cares about."
Those characters, more than the marauding walkers, are the secret to the popularity of the show, which averaged 13.8 million viewers last fall and was the top series in all of TV among young adults.
"It was apparent that it was about people dealing with a horrible situation, like Robinson Crusoe or the people on Lost," says executive producer Scott M. Gimple. "And how people come together, get in each other's way and mostly change."
Fans of Dead's roller-coaster action and constant threats won't be neglected, Gimple says. "There are going to be a lot of unusual walkers this season. And then there will be a different aspect to some of the walkers that can make them more dangerous."
Their numbers will grow, too. "There are absolutely more walkers around the prison, because there are more people in the prison," says Gimple, explaining the prison tenants must keep thinning the herd. "Suppose something got in the way of that constant maintenance. They'd be in trouble. They keep on stacking up at the gates."
And that won't be the only problem the survivors face, he says, promising "significant deaths" among the Season 4 threats: "Walker. Human. Other."
Producer changes haven't hurt the show's quality, and certainly not its ratings, Reedus says. (Robert Kirkman, a creator and writer of the comic books on which the series is based, remains an executive producer.)
Season 4 brings together elements from the three that preceded it, Reedus says.
"The first season was a hyperventilating breath and a heart thump-thump-thump about Rick waking up and an introduction to this world," he says. "The second season took a more dialogue-driven approach to explain things, and you needed that to tell a story. The third season was kind of just a war," he says. "The fourth season is all of those things combined, but it breathes in a way that you learn what's inside the characters, what drives them and what's destroying them at the same time. It's really gut-wrenching."