
Ben Cartwright is the patriarch of an all-male Nevada ranching family. Set during and after the Civil War, "Bonanza" is the story of life on the family's thousand-acre spread, known as the Ponderosa, near Virginia City. Ben has his three sons, each with a different (and deceased) mother. Serious eldest son Adam hopes to follow in his father's footsteps; middle son Hoss is a gentle giant -- physically strong, but sometimes naive; and youngest son Little Joe is the most impetuous and romantic of the offspring.
A sheriff's daughter runs off with her boyfriend (John Ericson), unaware he is a murderous bank robber.
An outlaw joins the Cartwrights' cattle drive, knowing it will take him to the town where his father is the sheriff.
The Cartwrights' neighbor (Franchot Tone), a former soldier and lawman, seeks security for his daughter.
Adam is taken hostage by a band of U.S. Army prisoners who have escaped and sought refuge on the Ponderosa.