“They may not seem like much one at a time. But in a group, all riled up and hungry -- you watch your ass.” -- Morgan Jones

If, even after countless previews and interviews with producers, there were any doubts that AMC's adaptation of The Walking Dead would be unflinching in its depiction of violence, they were undoubtedly laid to rest in the opening moments of the premiere.

Deputy Rick Grimes (Andrew Lincoln) arrives, gas can in hand, at an abandoned service station and adjacent camp, only to find empty and burned-out vehicles and a flyblown body. Hearing a noise, he peeks under a car to see a teddy bear and the slippered feet of a girl, who picks up the tattered stuffed animal as she shuffles by. "Little girl?" Rick says to the child in a soiled bathrobe. "Don't be afraid." She turns, revealing herself to be a Walker -- that's the series' term for a zombie -- and, growling, charges toward him. Without hesitating, the deputy raises his service revolver and fires, killing the blond moppet with a shot to the forehead.

It's an important scene because, not only does it quickly introduce the undead element before the episode reverts to something resembling an early-'70s road movie (the car chase and shootout that lead to Rick's coma), it provides an interesting contrast to the more compassionate, conflicted deputy we meet after the opening credits, when the story rewinds. After his initial horror and disbelief, Rick expresses pity for the Walkers -- something we don't often see in the zombie subgenre. When he encounters a "turned" fellow deputy, Rick immediately moves to put the creature out of his misery: "Leon Bassett? Didn’t think much of him -- careless and dumb. But I can’t leave him here like this." Then there's the infamous Bicycle Girl, the legless (ahem) Walker who drags herself around by her arms. Repulsed as he takes the bike she's no longer able to ride, Rick later returns to search for her, saying, "I'm sorry this happened to you" before shooting her in the head.

But I may be getting ahead of myself. Comic fans are by now likely familiar with the set-up for The Walking Dead, the long-running Image Comics series by Robert Kirkman, Tony Moore, Charlie Adlard and Cliff Rathburn: Rick Grimes, a small-town police officer (changed to a deputy sheriff for the TV show), is wounded in the line of duty and awakens in the hospital to discover that the world has been devastated by a zombie apocalypse. So he sets off for Atlanta in search of his wife and son. Director/Writer/Executive Producer Frank Darabont uses that as a road map for the pilot episode, "Days Gone Bye," deviating from the source material in ways that greatly benefit the story. Whereas Kirkman & Co. devote a single page to the shootout, and Rick's life before he awakes in the hospital, Darabont takes his time, establishing the friendship between Rick and his partner Shane (Jon Bernthal) and uncovering brewing problems in his marriage to Lori -- crucial elements missing from the early issues of the comic.

Darabont also toys with expectations, perhaps for the benefit of fans of the comic who think they know what will happen: Rick is shot in the standoff with the fugitives, just like in the comic, only to reveal he's wearing a bullet-proof vest. But when he turns to make Shane promise not to tell Lori, he's felled by another blast. Then again, in the hospital, a visiting Shane delivers a vase of flowers to his wounded partner, who seems to respond -- only to realize the flowers are dead and Shane long gone. They're both solid moments that make fans question, if briefly, how events will unfold.

However, the best, and most rewarding, deviation is Darabont's development of Morgan Jones (Lennie James) and Duane Jones (Adrian Kali Turner), the father and son who find a despondent Rick outside his empty home, and take him in (after Duane beans him with a shovel). In the comic's first issue, they serve as Rick's, and the audience's, introduction to the new status quo, delivering information about the Walkers. Here they play the same role, but they're given a tormented backstory -- one in which they're (literally) haunted by their undead wife/mother, who is drawn to their house in a terrible pantomime of her old life. Morgan admits to Rick that they've "hunkered down" in the house, frozen in an attachment to his wife. But in a particularly heartbreaking scene, Morgan tries to sever that tie but finds himself unable to kill her.

Parting company with the Joneses, Rick heads for Atlanta, first by police cruiser -- his faint radio calls are heard by the survivors camp led by Shane, who's now in a tense, secret relationship with Lori (Sarah Wayne Callies) -- and then by horse. Although the city had been touted as a military-protected haven for refugees, it is, of course, a zombie-infested hellhole. The horde of Walkers quickly overtakes Rick, who's forced to take cover in an abandoned (but not empty) Army tank. Just as all seems hopeless -- indeed, there's a moment when Rick considers suicide -- Glenn's (Steve Yeun) voice breaks over the tank's radio: "Hey, you. Dumbass. Yeah, you in the tank. Cozy in there?" The camera pulls back, fittingly enough to the tune of Wang Chung's "Welcome to My World," to show the swarming masses of undead. It's not "The Sun Ain't Gonna Shine (Anymore)," as we heard in the show's trailer, but it'll do.

"Days Gone Bye" is a riveting, chilling and near-flawless introduction to The Walking Dead that balances scenes of slow-building dread -- Rick descending a pitch-black stairwell lit only by a series of fast-burning matches is masterfully shot -- with bursts of action and moments of outright horror. Darabont and cinematographer David Tattersall deserve heaps of praise for that, but so, too, do actors Lincoln and James, who deliver magnificent performances (so much so that we can forgive their shaky accents). Anyone who isn't moved by Rick's breakdown in his empty home or Morgan's struggle to shoot his undead wife may very well be undead themselves.

Zombie body count: 13

Human body count: None on camera, but the landscape is strewn with countless corpses (we don't know whether anyone was killed in the shootout)

Animal body count: 1 horse; poor thing

Grade: A