In just a few years, AMC (NASDAQ:AMCX) has risen to join the ranks of cable's elite. The success of shows like Mad Men and Breaking Bad has certainly helped, but the network's biggest success has been The Walking Dead, which returns Sunday night for the back half of its fourth season. While it remains a dominant force on cable TV, you have to wonder when its ratings will peak.

(Credit: AMC)

Zombie appeal

Before looking at the numbers, you need to understand the appeal of Walking Dead goes beyond the zombies and the gore. In many ways, the title of the show applies just as much to its living characters as the dead. Either way, it's a morality story.

The show's done so well because audiences can relate to the characters on an emotional level, and thanks to sharp writing and equally skilled acting, it feels like a sucker punch when one of them is written off the show (or multiple characters, as was the case with December's midseason finale).

While you can look at it as emotional manipulation, it still works and it doesn't feel like a cheap plug for ratings. Each move is calculated and is done for the greater good of the storyline. Producers don't relish the ability to write off a character because that means they lose a gifted member of their cast at the same time. 

'Dead' Rising

Dead's fans are also very loyal and very vocal. The cast are treated like rock stars at events like Comic-Con, and they make sure to return the favor. The group understands the fans are responsible for their success and when the fans aren't happy, they are quick to calm their fears. The actors have earned that type of trust.

While the first half of this fourth season was a little slow for fans' tastes, the cast kept promising it was going somewhere ... and it did. It may have been a slow burn, but when the fuse ran out, it was a massive boom that literally blew up their world and has set into motion what could be a fascinating run of episodes.

That shift was also felt in the ratings. When Dead ended the first half of its season last year, it exited to 12.1 million viewers, a 15% gain year-to-year. Over those first eight episodes, the show on average hit around 13 million viewers a week, which season-to-season was a 29% jump. This is also the first season to score double-digit numbers for each new episode. In fact, its lowest rated installment pulled in 11.2 million viewers, and that was not only over a holiday weekend, but up against a Sunday Night Football matchup of the Patriots and Broncos.

Only when you're talking about the highest-rated cable show ever and the number one show in the all-important 18-49 demographic does "only 11.2 million viewers" give you pause. But the show opened to a record 16.1 million viewers, meaning a sizable viewer drop from September to December and the biggest premiere-to-mid-season-finale decline in the show's history. Season two slipped from 7.26 million viewers to 6.62 million viewers, while season three barely saw a blip, dropping from 10.9 million viewers to 10.5 million viewers.


The future

This week's episode is important for a number of reasons, not the least of which is it will set the stage for a trio of new cast members to eventually join, including one played by fan favorite actor Michael Cudlitz (Southland).

It also will give viewers and executives an idea of where the show is with its fans. Each "return" episode has netted solid numbers for the show. It's important for AMC's highest rated series to come back strong as it heads toward its March finale, because each of the previous three season cappers have set new viewing milestones. But this is the first time people are beginning to wonder if a similar jump is possible, given how high the season started.

Still every time we begin to discount the power of the drama, that loyal fan base roars back. The audience has yet to let the show down yet and likely will keep supporting it for some time to come, which means we probably haven't seen its peak yet. Personally, I still think 20 million viewers is in the cards at some point.

Dead is a critical cornerstone of the network's schedule. With the exit of Breaking Bad and the eventual departure of Mad Men in 2015, AMC needs the show to continue to thrive until it finds its next big thing. Dead captured lightning in a bottle and AMC has an interesting upcoming slate, but it remains to be seen if anything will hit it anywhere near as big for the network in the foreseeable future.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.