A former confederate soldier journeys to the transcontinental railroad to seek vengeance.

Cullen's search for the sergeant is diverted by an unexpected obstacle. Durant organizes a search party to retrieve the missing Lily Bell.

Cullen closes in on the Sergeant. Durant pursues a hidden agenda while helping Lily recuperate.

Durant attempts to end ongoing negotiations with the Cheyenne by challenging them to a competition.

Durant and Lily travel to Chicago - he, to further discuss the railroad with Senator Crane; she, to meet with her deceased husband's family. The Irishmen from Hell On Wheels prepare to hang Elam. Cullen interferes and helps him escape.

Cullen and the search party find the natives who attacked the surveyor's camp and later derailed a train; Elam and Eva discuss their future, before getting a strange visitor; and the railroad crew reaches the important 40-mile mark.

Durant and Lily conspire to gain investors' interests. Sean and Mickey McGinnes exact their own revenge on The Swede. Elam and Eva each begin to see the future differently. Cullen tracks down the elusive Sergeant Harper.