Alexa Mansour and Aliyah Royale in 'The Walking Dead: World Beyond' (Sarah Shatz/AMC)
CNN  — 

With the end of “The Walking Dead” now officially on the horizon, efforts to wring additional life out of the franchise have taken on greater significance – and for AMC, urgency. Yet “The Walking Dead: World Beyond” is a minor excursion, feeling too much like the Disney Channel version of a zombie show, minus the catchy songs.

Described as a two-season limited event, the new program certainly gets a splashy launch, following the months-delayed season finale of the flagship program, which was forced to end early due to coronavirus, as it approached the conclusion of the way-too-drawn-out Whisperers story arc.

Without giving anything away, that “Dead” episode features the kind of epic scope that the series can deliver at its best (as increasingly rare as that might be), which only compounds the sense that “World Beyond” represents “Walking Dead High School,” an overt attempt to appeal to a younger demographic with a spinoff nobody really needed.

That’s only a slight exaggeration, since the focus here sits squarely on a quartet of teenagers raised behind cloistered walls, who decide to take the not-very-bright step of embarking on a quest in pursuit of two of the girls’ dad. He’s a scientist who left to assist a shadowy outfit known as the Civic Republic, which won’t even divulge its whereabouts to the other colonies that have reinstated some sense of normalcy to this post-apocalyptic landscape.

The sisters, Iris (Aliyah Royale) and Hope (Alexa Mansour), have been relatively sheltered since the traumatizing loss of their mother a decade earlier – at least, enough so that they can talk about throwing “ragers” – and have pursued very different paths since then.

Norman Reedus in 'The Walking Dead' (Jackson Lee Davis/AMC)

Iris is a model citizen, but she’s plagued by nightmares, while her rebellious sister has become openly surly toward authority. That includes not only two community security officers (Nico Tortorella and “The Americans’” Annet Mahendru) trying to teach the younger set to survive but a representative of the Civic Republic (Julia Ormond) whose motives remain sketchy.

There is something mildly refreshing about the teens’ fairly inept steps outside their protective walls, reminding us that killing zombies can be harder than it often looks in the main show and “Fear the Walking Dead.” But there’s minimal investment, through two episodes, in the story or characters, including the awkward pair of boys (Hal Cumpston, Nicolas Cantu) that, for different reasons, tag along on Iris and Hope’s big adventure.

“The Walking Dead,” by contrast, finally enjoys a renewed sense of purpose as its 10th anniversary nears, with the prospect of a finale (even with a spinoff planned) and a former regular returning to help offset the high-profile cast departures. That combination offers at least the promise of greater momentum than the last few seasons have possessed.

As for “World Beyond,” the idea of a post-apocalyptic community facing uncertainty about what lurks outside brings to mind “Jericho,” a better series (set after nuclear devastation) that CBS aired in 2006.

“I can’t look away anymore,” Iris says in the premiere, citing her objective of “building a better future.”

In terms of the present, it’s too bad the producers didn’t build a better premise.

“The Walking Dead” and “The Walking Dead: World Beyond” air Oct. 4 at 9 and 10 p.m. ET, respectively. “Fear the Walking Dead” premieres Oct. 11.