The latest Walking Dead season 4 commercial reinforces talk that in the upcoming episodes, a new threat from the zombies will cause big trouble for Rick and company.

The commercial, which aired last night on AMC, shows that in The Walking Dead season 4 the zombies will be able to break through the fences.

“Everything we’ve been working so hard to keep out, just found its way in,” says Hershel ominously. In the footage we see a sight that the prison inhabitants will not be happy with.

This plot point is evident in The Walking Dead season 4 poster released last week. In it, Rick stands in a hole in the fence that must’ve been torn open by zombies.

Will this mean everyone will have to move out of the prison? Or will the humans develop a new way to block the prison from zombies entering?

Yesterday, we shared a promo which shows Daryl and Michonne dealing with zombies as they’re on the road.

The highly-anticipated return of AMC’s zombie drama returns on Sunday, October 13 at 9 p.m. eastern/pacific. The first episode is titled “30 Days Without An Accident,” and it looks like the show will time jump a bit in between season 3 and season 4. Since we last saw everyone at the prison, Woodbury’s residents have now moved in with Rick and creator Robert Kirkman recently showed off what kind of upgrades have happened at the jail.