By Sara Smith, The Kansas City Star (TNS)

The zombie apocalypse goes viral in “Fear the Walking Dead,” a serviceable but less-than-stellar spinoff of AMC’s hit series “The Walking Dead.”

“When civilization ends, it ends quickly,” one wise kid observes when things start to fall apart. For the ramshackle family of three adults and three teenagers at the heart of this new show starting Sunday, things weren’t holding together so well in the first place.

To understand where “Fear” fits in the world of “The Walking Dead,” you have to rewind all the way to that show’s very first episode, which aired on Halloween 2010. “The Walking Dead” began its story through the eyes of sheriff’s deputy Rick Grimes (Andrew Lincoln), who had nearly died from gunshot wounds after a high-speed chase.

When Rick emerged from a coma in an abandoned hospital, he found a world already torn apart by the undead. Rick figured out that he’d been in the hospital for about 90 days while chaos raged. “Fear the Walking Dead” takes place during those three months.

Just like its predecessor, “Fear the Walking Dead” begins with a central character opening his eyes to a nightmarish reality. Nick, a junkie college dropout, wakes up from his latest needle nap to see his pretty blond girlfriend snacking on a dead guy’s face.

Because he has been addicted to heroin for years, no one’s taking Nick’s word for what he saw, especially after he runs into traffic and ends up strapped to a hospital bed. Nick (Frank Dillane) wants to believe he might have been hallucinating those ravaged bodies and pools of blood, too.

When Nick’s mom, Maddie (Kim Dickens), and her boyfriend investigate the abandoned church serving as a drug flophouse, they find the pools of blood but no bodies. “They didn’t just get up and walk away,” says Travis (Cliff Curtis). Oh, the naive disbelievers of the early days.

Sirens blare and traffic clogs as rescue vehicles speed through neighborhoods, but no one has begun to connect the nasty virus keeping people home and the increase in police shootings. Its prequel status makes “Fear” a bit predictable, so its observations on societal breakdown are more compelling than its main characters during the initial exposition-heavy episodes.

The Internet gives Angelenos their first clue that something is very wrong. Leaked news footage of paramedics being attacked by recently dead victims of a car crash leads to rumors of a potent new drug or virulent illness. The video ends with police filling a staggering citizen with a staggering number of bullets, until a shot to the head finally takes him down.

Kids with iPhones watch the scene on their 5-inch screens, not knowing they’ll soon get better phone service from tin cans and a string. One of those kids is Maddie’s daughter and Nick’s little sister, Alicia (Alycia Debnam-Carey), a junior in high school who clings to her snotty attitude, her artist boyfriend, and her acceptance letter to Berkeley.

Alicia’s school shuts down right around the time that her mom and Travis are getting their first glimpse of the threat up close, leading to a frantic search for Travis’ ex-wife, Liza, and teenage son, Chris. Roads are being closed, the power grid flickers, and suburban doomsday preppers are starting to look pretty smart.

While Liza (Elizabeth Rodriguez) assumes that Travis’ frantic calls are a custody power play for an extra weekend, Chris (Lorenzo James Henrie) gets caught up in one of the spontaneous protests caused by police interacting with the undead. It’s not hard to imagine a scared public blaming cops for executing the “homeless” without the knowledge that they’re really zombies. With their bad posture and tenacity, these L.A. undead very well could be listless drunks, zonged out on bath salts, or just lost on their way to Starbucks.

The zombies in “The Walking Dead,” or “walkers,” as they’re called, are slow-moving, half-rotted, dull-witted. They don’t stop in their relentless pursuit of fresh flesh, but they don’t exactly sprint, either.

But these new walkers are freshly dead, and they’ve quickly lost their coordination, but they’re not apathetically shambling through the backwoods of Georgia. In “Fear the Walking Dead,” the zombies are faster, and the living are slower.

A day before the inevitable riots, Travis was teaching Jack London survival metaphors to sleepy-eyed teenagers who scoffed at the idea that they’d ever have to build a fire. Suddenly he’s holed up with strangers in a barbershop, waiting for the worst to pass so he can gather his makeshift family and head for the desert.

“The Walking Dead,” like “Revolution” and other post-apocalyptic fare, dropped its viewers into a world where technology had become irrelevant and survivors had embraced their inner Boy Scouts. “Fear the Walking Dead” is a mid-apocalyptic tale where no one is equipped for the coming reality. Naturally, they turn again and again to their failing gadgets. “Dead again!” they complain, thinking they’re just talking about their phones.

“Fear the Walking Dead” isn’t essential TV for anyone but “Walking Dead” fanatics, but with just six episodes in its first season, it’s a fast-paced, character-driven look at the power of information. Travis and Maddie know more than most people, and that’s the only reason their family might last until the fires die down.

“Fear the Walking Dead” premieres at 8 p.m. Sunday on AMC.

Photo: Elizabeth Rodriguez and Lorenzo James Henrie in “Fear the Walking Dead.” (Frank Ockenfeis 3/AMC)