In the next episode of "Z Nation," Murphy (Keith Allan) and the rest of the survivors follow Roberta Warren (Kellita Smith) across a landscape of rubble and destruction.

The trailer for the upcoming installment titled "A New Mission: Keep Moving" was released just recently and showed Warren taking the lead as Murphy, 10K (Nat Zang), Doc (Russell Hodgekinson), and Lucy (Tara Holt) follow her through the Great Pile, which is a massive wasteland of rubble and metal wreckage. However, they encounter other survivors who entrap them among the ruins. An electrified net wraps around Doc and Lucy who fall to the ground unconscious.

Meanwhile, a mysterious soldier corners Murphy, holds out her gun and aims at him. Fortunately, Warren is behind her and knocks her out with a metal shield. They also encounter some zombies as they stealthily make their way through the pile of cars and junk. "America is looking better all the time," Murphy tells the group in a sarcastic manner.

It remains to be seen who trapped Doc and Lucy in a net and how the survivors escaped from their clutches.

In the last episode, Warren and the survivors took refuge at the camp and had an idea that the zombie virus may have mutated and made the undead more powerful. They were able to witness this firsthand when the zombified Lt. Mueller (Henry Rollins) returned to the camp all rabid and out of his mind. Warren unleashed a hail of bullets at Mueller who got hit mercilessly and went down. All of a sudden though, he started to get up again and charged at the survivors.

Sgt. Lily (Gracie Gillam) then stepped in and blew zombie Mueller's head off with a shot gun. Apparently, a zombie cannot be killed just by shooting the head.

"Z Nation" season 4 episode 4 will air on Friday, Oct. 20 at 9 p.m. EDT on the Syfy channel.