Following a harsh winter, Cullen convinces the Credit Mobilier board to appoint him Chief Engineer of the Union Pacific railroad. Collis Huntington, head of Central Pacific railroad, asks Cullen to join him instead. Cullen declines.
In jail, Durant reprimands Senator Metcalf for allowing Cullen to be reinstated. Durant wants to run the railroad through Metcalf’s son-in-law.
Cullen tours Hell on Wheels with Louise Ellison, a reporter for the New York Tribune who’s writing a story on the transcontinental railroad.
After Mormon homesteader Aaron Hatch orders Cullen to keep the railroad off his property, Cullen visits his farm. In a barn that night, Cullen seduces Hatch’s daughter, Naomi.
In Omaha, Durant proposes a railroad terminus on rancher Maggie Palmer’s land.
Sean, now Cullen’s bookkeeper, secretly meets with Durant. Sean gives Durant the Union Pacific telegraph routing code so Durant can eavesdrop on Cullen.
Because routing around Hatch’s farm would put Cullen behind schedule, he sends Elam and Dick Barton to order the family out. The Chief of Railroad Police is shot and killed so Elam takes his place.
Backed by cavalry, Cullen presents Hatch with a writ of execution for Dick’s murder. Hatch blames his eldest son, who is hanged.
When the railroad’s cattle is stolen, Cullen initially believes Indians to be responsible and orders Major Bendix to retaliate. Bendix exterminates a nearby Indian village.
Upon discovering the wranglers were not Indians, Cullen accuses Durant, who denies any involvement. Maggie Palmer offers Cullen a deal on cattle.
Declan Toole (Gregory’s brother) arrives in Hell on Wheels to marry Eva, per Irish custom. She refuses. Elam tells Declan to stay away.
The Swede travels with the future Mormon bishop Joseph Dutson and his family.
Cullen and Elam play a deadly game of stickball to broker a deal with the Kiowa for trees to replace rail ties destroyed in a fire.
Durant tells Louise that Cullen is a murderer, providing names of his victims.
Eva’s baby is stolen. The Freedmen blame – then attack — Declan. Cullen and Elam eventually find the baby, a process that puts the railroad two weeks behind schedule.
The Swede kills Joseph and Eleanor Dutson. Their son, Ezra, escapes.
General Ulysses S. Grant joins the Credit Mobilier Board in Hell on Wheels to hold a competency hearing for Cullen. Grant agrees to let Cullen to keep his job if he gets the railroad to Cheyenne in 20 days.
Cholera hits Hell on Wheels. A group of workers desert for the nearby Mormon fort. Cullen searches for fresh water and, near death, encounters Ezra, who leads him to a spring.
Senator Metcalf tries to grab railroad stock certificates from Durant. Durant shoots him dead then blames Sean. Mickey helps Sean dispose of the corpse via a burning mass grave of cholera victims.
The Swede assumes Bishop Dutson’s identity in the Mormon camp.
Eva gives her baby to Declan. Elam kicks Eva out.
Boston detective Malone questions Durant and Sean about Senator Metcalf’s whereabouts.
Outside the Mormon fort, Cullen sees Collis Huntington exit. Huntington says, the Mormons are building their own spur line to Cheyenne and he now owns their workers.
Cullen secretly approaches the fort and convinces the deserted Union Pacific workers to return to Hell on Wheels.
Eva begs Mickey for a job. He refuses. Louise lets Eva stay with her.
In the church, Sean starts to tell Ruth a story about Mickey and two girls. Mickey shoots Sean then tells Malone, Sean confessed to Metcalf’s murder. Malone says, Sean was also wanted for murdering two women in Boston.
Durant invites Cullen to lunch in Cheyenne. Riding in, Cullen, Elam and Ezra are attacked by armed riders led by Aaron Hatch. Ezra is taken hostage. Cullen surrenders in exchange for Ezra’s release. Hatch takes Cullen to the Mormon fort.
Per Cullen, Elam leads the railroad to Cheyenne.
The Mormons hold Cullen captive. Hatch says, Cullen must hang for executing his son. At Cullen’s hearing, The Swede is introduced as Bishop Joseph Dutson. Hatch accuses Cullen of impregnating Naomi, who confirms Cullen is the father of her child. Cullen offers to marry Naomi to make good. The Swede weds the two.
Durant is given control of the railroad in Cullen’s absence.
A bear attacks Elam as he searches for Cullen.
Cullen plows a field in the Mormon fort as the Union Pacific train whistles in the distance.