Three years into the zombie apocalypse, a ragtag team of everyday heroes comes together to transport the only known survivor of the zombie virus from Upstate New York to a lab in California, in hopes of using his blood for a vaccine. A zombie baby proves to be an early obstacle, and what they don't know is that their last, best hope for a vaccine is hiding a dark secret that threatens them all.

In New Jersey, the survivors run out of fuel and embark on a dangerous mission to replenish their supply. Meanwhile, Cassandra's past comes back to haunt her.

The survivors make their way through the mean streets of Philadelphia, where they cross paths with a group of psychotic outlaws with ties to one of their own.

The survivors visit Warren's home town in Central Illinois, but will they find her long missing husband? Oh, yeah - there's also a zombie tornado that leaves everyone in danger.

An encounter with a seeming Utopian enclave and a religious cult results in a game changer when the survivors travel near Branson, Mo.

The survivors struggle to recover from a shocking death; and in Kansas they happen upon a gun show that makes the zombie apocalypse look calm.

As they travel across Nebraska, the group finds themselves trapped in a morgue as a literal zombie tsunami engulfs them; at the same time, Citizen Z gets a visitor who might not be who he seems to be.

Mack attempts to go on a real date with Addy, but ends up stuck in some Groundhog Day-like nightmare.

The survivors square off against radioactive zombies when they arrive in a South Dakota town that's on the brink of nuclear disaster.

The two groups of survivors reunite in Utah, where they come upon an all-female commune that seems like paradise—that is, until someone ends up dead.

Murphy is kidnapped by a group of outlaws trying to crack the "Fort Knox of Oxycontin." As the survivors battle drug-enhanced zombies, a startling discovery is made about Murphy's abilities.

The team is rerouted to a Colorado lab where they hope to find Dr. Merch.