Though the ratings for The Walking Dead have remained high, behind-the-scenes shake-ups at AMC's zombie-fest have meant that the show has spent years failing to live up to its potential. It started with showrunner Frank Darabont, whose dramatic exit from the show resulted in an ongoing legal battle with AMC for lost revenue. The second showrunner, Glen Mazzara, ceded the chair to its current occupant Scott Gimple before season four began — leading some to worry that the instability could have a fatal effect on the series.

Fortunately, the exact opposite has happened. The Walking Dead used the first half of its fourth season to rebuild and refocus, blowing the story wide open for the back half of the season, which premiered last night — and it was a glorious return to form for a show that has so often struggled. This is how The Walking Dead has rediscovered its footing, and given its already loyal fan base a reason to stick with the show even more ferociously:

1. The narrative is more focused
The Walking Dead's lowest point came in the second season, when the show camped out at the farm and dragged out several soapy storylines for far too long. And even in stronger episodes, the sprawl of the ensemble cast could get a little overwhelming.

So in last night's premiere, it was refreshing to see the show spend a substantial amount of time with just a handful of characters. The show lavished attention on Rick and Carl's story and the lone wolf Michonne, and made those moments count. By lasering in on a few tight stories, the show had significantly more impact than if it had repeated the past mistake of cramming in as many character revisits as possible.

2. The uncertainty has returned
To its credit, The Walking Dead has always remembered that for all its narrative twists and turns, there's something undeniably frightening about a zombie jumping out from behind something to scare the bejesus out of its characters and viewers. The back half of the season is upping the scare stakes even further: After far too much time in the relative safety of the prison, our protagonists are out wandering the great, terrifying unknown.

(Gene Page/AMC)

3. Human relationships are driving the narrative
To balance out all the exploding zombie skulls and hanging bits of rotting skin, The Walking Dead has to be driven by human relationships. In a slow burner like last night's premiere, the show benefited not by adding more gore, but by spotlighting the tense and deeply fractured relationship between a father and son.

Rick is seriously injured after his battle with The Governor and is no longer seen as a hero by his son Carl, who blames his dad for Hershel's death and the (presumptive) loss of his baby sister Judith. Meanwhile, Carl isn't a little boy anymore and, like most teens, is indignant that his father won't recognize his purported adulthood. It's a classic parent-child struggle — except, of course, that this parent and child are fighting for survival in a zombie wasteland.

4. The bleakness is back
Within the confines of a drama, it's scary to have the protagonists questioning the purpose of staying alive — and if The Walking Dead were a tidy, two-hour horror movie, such a idea would likely never enter into the fray. The beauty of this TV show existing over so many seasons is how it allows the truly existential question of "why?" to pop up over and over again. The Walking Dead's characters live with such total bleakness and absorbed trauma that viewers are constantly reminded that this isn't a video game or cheap thriller. After fumbling its central narrative for awhile, The Walking Dead has successfully recaptured the idea that these are humans fighting for survival with no clear endgame in sight.