A fiesty Quebec trapper meets Arapaho Chief Lame Beaver in his travels throughout the American West. Thus beginning a series of relationships that create a timeline of adventures from the late 1700's to the 20th century. On a trip to St. Louis to sell his wares, he encounters the wealthy silversmith Herman Bockweiss (Raymond Burr) and enters a partnership with him to bring guns and silver to the Indians. He agrees to marry Bockweiss' daughter Lise (Sally Kellerman) and leaves shortly thereafter to return to his trapping trade. He encounters and saves the life of his future partner, Alexander McKeag (Richard Chamberlain), a Scotsman attempting to escape his past. They make their way to an Arapaho camp where McKeag, who has been injured, is tended by Chief Lame Beaver's daughter, Clay Basket (Barbara Carrera). They fall in love, but she instead marries Pasquinel at her father's request. Accompanied by Clay Basket, the partners set out in search of Pasquinel's true desire - gold.

In spite of mounting tensions between the races, Pasquinel, McKeag and the Indians continue a profitable releationship in trading. Clay Basket bears Pasquinel two sons, Jacques and Marcel, while back in St. Louis, Lise gives birth to Pasquinel's daughter, Lisette. Pasquinel continues his obsessive search for Lame Beaver's gold, while McKeag and Clay Basket are secretly in love with each other, but her honor in marriage to Pasquinel won't allow her to reveal it to McKeag.

1845: In Lancaster, Pennsylvania, young Mennonite Levi Zendt heads out west with his bride-to-be Elly Zamm. On the wagon train and in St. Louis they meet young English writer Oliver Seccombe and Army Captain Maxwell Mercy - who is married to Lisette, Pasquinel's daughter. McKeag weds Clay Basket and adopts her half-breed daughter Lucinda. While on the wagon train, guide Samuel Purchase tries to rape Elly, causing Levi and Elly to leave it, meeting McKeag and later establish the settlement of the town Centennial.

Driven by the grief over his wife's death, Levi boards himself up in the desolate cabin once used by McKeag and Pasquinel in their early trapping days. Clay Basket and McKeag soon send their daughter Lucinda to bring him to their home. Eventually, Levi and Lucinda fall in love and marry. Meanwhile, Hans Brumbaugh arrives from Germany to seek gold.

Representing a group of British investors, Oliver Seccombe arrives in Centennial with money to start a cattle ranch. He hires John Skimmerhorn to get some men and launch a large cattle drive to the West's largest cattle ranch, the Venneford. Skimmerhorn hires R.J. Poteet, an experienced trail boss, who picks a handful of seasoned drovers and young trail hands.

Mervin Wendell, his wife Maude and son Philip, a theatrical / professional con man comes to Centennial. Jim Lloyd is in love with Levi Zendt's beautiful, but wild daughter Clemma and pursues her. Meanwhile, the British investors have sent Scottish accountant Finlay Perkin to the Venneford Ranch to do an audit. Not able to understand Seccombe's accounting or spendage of running a cattle ranch, he accuses him of thief.

The Wendells easily con the people of Centennial, while blackmailing Reverend Holly. The Wendell son, Philip idolizes Sheriff Dumire, who is investegating the disappearance and possible murder of a traveling businessman, carrying a briefcase full of money. Newly widowed Charlotte Seccombe, returns to England briefly, but returns to run the Venneford Ranch. Meanwhile, Hans Brumbaugh, with the help of Japanese laborers has built his farm into a successful potatoe farm.

Charlotte Seccombe and Jim Lloyd fall in love, while Zendt's troubled daughter Clemma returns. The notorious Pettis gang arrive for a showdown with Sheriff Dumire. Hans Brumbaugh's Japanese laborers quit him to follow after their own dreams of owning their own farms.

Early 1900's, Mervin Wendell has become a real estate tycoon by selling promises on land that barely produces any growth to young naive families from the East. While Charlotte Lloyd takes up the Mexican residents' cause at defending their rights.

1978: Historian Professor Lew Vernor and writer Sidney Enderman arrive to do a article on Centennial. Paul Garrett, the current owner of the Venneford Ranch and a direct descendant of Pasquinel, tells them the history of the town. Morgan Wendell, son of Philip is running for the newly formed office of Commissioner of Resources and Priorities for the State of Colorado. When it is realized that Wendell is running only for the money and power, Garrett is persuaded to run against him.