Cullen is in California with the Central Pacific Railroad, and must learn to contend with the new workers; word comes in from Salt Lake City about the Hatches.
Cullen enlists new workers to help him move a locomotive on a sled; Cullen and Fong must work together; Swede and Phineas fight for survival after being banished to the high country.
Cullen must deal with the violence in Chinatown, caused by disgruntled workers; Phineas is manipulated in his plot against the Mormons.
In the wake of the violence, Cullen solves a Chinese labor strike; Mickey is pulled deeper into Union Pacific Business.
Violence erupts during the festival of Tin Hau Don in Chinatown; Cullen confronts the Swede; Durant gets Maggie involved in his latest scheme.
Cullen and Mei escort precious cargo through the California wilderness; Eva nurses Louise back to health.
Cullen and Durant meet with President Grant to discuss the future of the railroad; the Swede puts his plan against the Mormons in action.
When the Swede goes on a murderous rampage on the Hatch homestead, a long-overdue showdown with Cullen ensues.
Cullen's nitroglycerin experiment makes an explosive backdrop for the railroad life in Truckee; Durant's plan takes a deadly turn.
Mickey has blood on his hands after working with Durant; Campbell returns to town, complicating Louise's life.
Chang forces Mei to leave Truckee after discovering her secret; Cullen exorcises some old demons during his search.
When the race to finish the railroad comes down to mere inches, all parties find themselves pondering the end of the line and what the future has in store for them.
Government hearings, incalculable actions and the golden spike breed new beginnings and endings for those left standing.
Cullen awaits the birth of his baby; Durant must deal with the fallout following a railroad accident.
As Cullen plans an exit from Fort Smith, he challenges The Swede; when a new adversary arrives, Cheyenne feels his presence.
Cullen returns to work on the railroad, and clashes with his new boss; Durant and Campbell battle over valuable real estate.
Cullen handles trouble at home and takes railroad matters into his own hands; Campbell makes a move against Mickey and Durant.
Cullen's family is at risk when a stranger arrives, stirring up old feelings; The Swede faces the consequences.
Elam tries to recover in a Comanche village from a savage bear attack, to make his way back to Cheyenne.
In order to ensure his family's safety, Cullen makes a decision; Campbell hires a new federal marshal with hopes of cleaning up the streets.
Cullen faces off against the new marshal to recover his arrested railroad workers; Campbell confronts Louise.
Cullen, Durant and Campbell try to negotiate a settlement on how the streets will be policed; an act of terror strikes Cheyenne.
Cullen and Durant work to save the life of a criminal; Louise supports Ruth as she copes with a loss.
Cullen struggles with Ruth's unexpected decision; Louise risks her reputation to fight for a story she believes in.
As the railroad prepares to leave Cheyenne behind after Sherman Peak; Cullen returns to Fort Smith to get his family.
Cullen and Elam secure their railroad positions in New York; Durant fights for his legacy from prison.
Cullen and Elam search for their stolen food on the prairie; a stranger's arrival threatens Elam's family.
Cullen and Elam try to secure a new lumber source following a railroad accident; Durant tells Louise a secret about Cullen.
Cullen helps Elam track down a dangerous criminal; the town prepares to move down the tracks.
Durant files an injunction against Union Pacific, threatening Cullen's position; Elam deals with a dangerous newcomer.
A cholera epidemic breaks; Cullen must locate fresh water before his employees perish; Durant faces political fallout.
Cullen seeks help from Durant in winning his workers back from the Mormons; Sean and Mickey are haunted by their past.
Riders attack Cheyenne; Cullen and Elam visit Durant; General Grant's deadline approaches.
Cullen deals with consequences; Elam mounts a rescue attempt; Durant receives the U.P. board ahead of the deadline.
Cullen and Elam are on opposite sides of the law; Durant and Lily push the railroad west.
Durant confronts a threat to Hell on Wheels; a crime forces Lily and Elam to strike a deal.
Mickey and Sean's lives hang in the balance; Cullen tries to keep order; Lily and Elam work together to clean up a mess.
Cullen has to diffuse an internal threat to the railroad; tragedy strikes.
Cullen is haunted by his past; the fate of the railroad hangs in the balance.
Durant fights for his life and the railroad; Cullen tries to save an old friend.
A new arrival brings chaos; Eva is caught between Elam and Mr. Toole.
Cullen is interrogated about the destruction of Hell on Wheels.
Cullen and Lily take over the railroad and the Sioux attack; Eva attends Toole's funeral.
A former confederate soldier journeys to the transcontinental railroad to seek vengeance.
Cullen is diverted in the search of the sergeant; Durant organizes a search party to find Lily Bell.
Cullen closes in on the sergeant; Durant has a hidden agenda while helping Lily recuperate.
Durant's answer to the railroad's financial problems spurs a brawl between Cullen and Elam.
Durant attempts to end ongoing negotiations with Cheyenne; Cullen and Elam scramble to prevent bloodshed in town.
Cullen must decide how much he is willing to risk; Durant faces financial ruin; Lily confronts the family of her late husband.
Cullen and Elam are on a mission of vengeance; Lily struggles to find her place.
Cullen and Lily work to meet the railroad's deadline; Elam and Joseph deal with the consequences of their violent mission.
Cullen must choose between to dwell on the past or look forward to the future.