Cullen awaits the birth of his baby, laboring under The Swede's thumb at Fort Smith. Durant deals with the fallout from 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 goes back to work on the railroad and butts heads with his new boss. Durant and Campbell battle over a valuable piece of real estate.

Cullen deals with trouble at home as he takes railroad matters into his own hands. Campbell makes a move against Durant and Mickey.

Cullens's family is at risk when a stranger arrives, stirring up old feelings; The Swede faces the consequences.

Following an attack by a bear, Elam struggles to survive in a Comanche village and find his way back to Cheyenne.

Cullen attempts to reconnect with Elam upon his return. Durant takes matters into his own hands while putting an old problem to rest.

Cullen goes head to head with the new marshal to recover his arrested railroad workers. Campbell confronts Louise over a story.

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 fight to save the life of a criminal. Meanwhile, Louise tries to provide support as Ruth copes with a great loss.

Cullen grapples with Ruth's unexpected decision; Louise jeopardizes her reputation to fight for a story she believes in.

As the railroad prepares to leave Cheyenne behind in the Season 4 finale, Cullen returns to Fort Smith to retrieve his family.