At the onset of a zombie apocalypse, chaos descends as Rose loses her family, Ryan tries to get his bearings, and a desperate man finds a new guise.

Cullen grapples with consequences while Elam mounts a rescue attempt. Durant receives Gen. Grant and the U.P. board in Cheyenne ahead of the deadline.

After his workers defect to the Mormons, Cullen recruits Durant to help get them back. Meanwhile, Sean and Mickey’s past comes back to haunt them.

With General Grant’s deadline only two days away, a gang of riders attacks Cheyenne while Cullen and Elam pay Durant a visit.