As the Civil War is fought between the North and South, militia colonel Frank Skimmerhorn arrives in Colorado on a mission to wipe out the Indians. Major Mercy struggles to keep the peace while the Pasquinel brothers face their final days. Hans Brumbaugh begins to farm the land and Oliver Seecombe brings the prospect of a new business.
John Skimmerhorn hires R.J. Poteet to lead the difficult cattle drive from Texas to Colorado on behalf of Oliver Seccombe and the Venneford Ranch. Sixteen-year-old Jim Lloyd joins the drive along with cowboys Nate Person, a former slave, Amos Calendar, and Bufe Coker. Meanwhile, Hans Brumbaugh vows to never sell his land to Seccombe.
The town is now called Centennial. The last of the Arapaho led by Lone Eagle leave for a reservation. Hans Brumbaugh refuses to be intimidated by the Venneford Ranch; a range war threatens to erupt when Messmore Garrett brings sheep to the area. Brumbaugh imports a Japanese family to help on his farm.
The circus comes to town and briefly reunites members of the Skimmerhorn cattle drive; Levi Zendt returns to Lancaster, PA for a visit; an accountant uncovers discrepancies in Venneford Ranch's books; a family of actors arrives under the watchful eye of Sheriff Dumire; and Centennial faces a harsh winter.
Oliver Seccombe resigns, but decides to never leave Colorado. The Wendells are determined to stay in Centennial, but can't shake the suspicions of Sheriff Dumire. The killing of the Pettis brothers is not forgotten and Charlotte Seccombe takes over Venneford Ranch. In addition a murder is hidden.
Philip Wendell is tormented as Sheriff Dumire continues his investigation. The Pettis gang is out for revenge. Clemma Zendt returns just as Jim Lloyd and Charlotte Seccombe become engaged. Mervin Wendell jumps at a business opportunity and the first Mexican workers come to Centennial.
In the early 20th century, the Wendells prosper and new families move to Centennial to farm in the dry lands. The Mexican immigrants face discrimination and exploitation. Several prominent citizens pass away while farms struggle during the Depression. Philip Wendell plans to run for Congress and the Grebe family falls victim to the Dust Bowl.
A magazine prepares to do a feature on the history of Centennial; the murder of Soren Sorenson is finally proved; Morgan Wendell and Paul Garrett face off in an election that may determine the future of Colorado's natural resources.