Lyman is a retired historian who suffers from a severe bone disease that required the amputation of his leg, leaving him confined to a wheelchair. Following the collapse of his marriage, he isolates himself in his family's ancestral home. Rather than write traditional history, he decides to dedicate his time to researching and recording the lives of his frontier-era grandparents.

Susan is a talented illustrator and writer who gives up a promising career and active social life in the East to marry an engineer. Relocating to a series of rugged mining camps, she strives to bring refinement and culture to the frontier. She finances her family during difficult times by selling articles and illustrations about her Western experiences to Eastern magazines.

Oliver is a pragmatic and hardworking mining engineer who feels most at home in the untamed American West. He lacks the social polish of Susan's Eastern friends but possesses a quiet, physical resilience. He frequently relocates his family in pursuit of ambitious engineering and mining projects, facing numerous professional setbacks along the way.

Shelly is a young college dropout and part of the 1970s counterculture movement. She works as Lyman's secretary, transcribing his dictated research while challenging his perspectives. Her modern frankness regarding relationships and history constantly pushes Lyman out of his academic comfort zone.

Augusta is a wealthy, well-connected woman living in the East. She is bewildered by Susan's choice to marry a Western engineer but remains faithfully devoted to their correspondence. Her highly successful life serves as a constant baseline against which Susan measures her own frontier struggles.

Thomas is one of America's foremost literary editors. He comes from a poor background but achieves immense success in New York. He actively supports Susan's career by publishing her letters and articles about the West in his magazine.

Ellen is Lyman's estranged wife. She abandoned their marriage during his severe medical crisis, initiating a relationship with the surgeon who amputated Lyman's leg. Her departure deeply wounds Lyman and serves as the catalyst for his obsessive dive into his grandparents' marital history.

Rodman is Lyman's adult son. He views his father's historical project as a waste of time and worries constantly about Lyman's physical safety in the old house. He prefers practical, modern solutions and lacks Lyman's sentimental attachment to the family's past.

Ada is Lyman's older caregiver and a longtime associate of the family. She handles his daily physical needs with routine efficiency. She brings her daughter, Shelly, into Lyman's orbit, though she frequently clashes with Shelly over the younger woman's lifestyle and boundaries.

Frank is a young, capable assistant who works with Oliver on various mining and engineering projects. Unlike Oliver, Frank shares Susan's interest in literature and music, bringing a touch of intellectual companionship to the isolated frontier settlements where the family lives.

Ollie is Susan and Oliver's eldest child. Growing up entirely in the West, his severe childhood fevers frequently cause Susan immense anxiety. He learns to adapt quickly to the dangers of the frontier environment.