Niel is a middle-class boy living in the railroad town of Sweet Water. Raised by his uncle following his father's business failure, Niel possesses gentle manners that distinguish him from the rougher sons of local tradesmen. He is highly observant, studies his uncle's classic texts, and quickly becomes fascinated by the refined lifestyle maintained by the wealthy Forrester family.

Marian is the beautiful, vibrant, much-younger wife of Captain Forrester. Hailing from a wealthy California background, she serves as Sweet Water's premier hostess, entertaining powerful railroad executives and locals with equal grace. She possesses a magnetic charm that captivates everyone she meets, though she secretly chafes against the quiet, provincial nature of small-town life.

Captain Forrester is a massive, dignified railroad contractor who built his fortune developing the American West. An officer in the Civil War and a gentleman of the pioneer class, he chose to settle in Sweet Water out of a deep appreciation for the area's natural beauty. He is a man of few words, characterized by his towering integrity, calm demeanor, and unshakeable honor.

Ivy is a cruel, ambitious local boy known to Niel and his friends as "Poison Ivy." He resents the upper-class citizens of Sweet Water, particularly the Forresters, and actively tries to prove he is just as good as they are. He aspires to practice law and delights in defying the natural beauty that men like Captain Forrester seek to preserve.

Judge Pommeroy is Niel's maternal uncle and a prominent lawyer in Sweet Water. He represents the fading aristocratic, honorable pioneer class alongside his good friend Captain Forrester. He takes Niel into his care and instills in him traditional values of hard work and gentlemanly conduct.

Frank is a striking, powerfully built businessman from Denver. He possesses a dark, slightly dangerous reputation from his youth, though he currently earns respect for caring for his elderly mother. Niel instinctively senses something unsettling about him when they cross paths at the Forrester home.

George is the son of a gentleman rancher and one of Niel's childhood friends. Like Niel, George possesses polite manners that set him apart from the rougher tradesmen's sons in Sweet Water.

Adolph is a German immigrant boy from a lower social class in Sweet Water. He acutely understands his place in the town's social hierarchy and deeply appreciates Mrs. Forrester's consistent kindness when he delivers fish and game to her back door.

Rheinhold is Adolph's brother, also a German immigrant boy. He participates in the childhood excursions on the Forresters' land but keenly understands the rigid class divisions that separate him from the wealthy elite.

Constance is the pretty but somewhat disagreeable young daughter of the Ogden family. She visits the Forresters alongside her parents and shows little interest in interacting with Niel, preferring the company of older, more powerful men like Frank Ellinger.

Orville is a quiet businessman who brightens noticeably in Mrs. Forrester's presence. He represents the class of successful men who frequently pass through the Forresters' home on their travels.

Mrs. Ogden is Constance's mother, who accompanies her family to Sweet Water. She is amiable and conversational, providing a polite contrast to her daughter's haughty demeanor during social events.

Tom is Judge Pommeroy's loyal servant. He is occasionally hired out by Mrs. Forrester to wait tables and assist in the kitchen during her elegant dinner parties.

Cyrus is the president of the Colorado & Utah railroad and a close personal friend of Captain Forrester. He deeply appreciates the Forresters' hospitality and considers their presence essential to his winter social life in Colorado Springs.

Ben is a local man who helps the Forresters with chores around their property. He frequently delivers their mail and supplies when they are isolated at their estate.

Annie is Ivy Peters' sister. She helps Mrs. Forrester with cooking and serving duties when the Forrester household entertains guests.