The series follows Christopher Colt, a suave and skilled gun salesman who traverses the American West with an unusual secret. While he appears to be solely concerned with peddling his wares, Colt is actually an undercover agent working for the U.S. government. He is tasked with infiltrating and dismantling criminal operations that threaten the growing nation. As Colt journeys to various towns and unsettled territories, he encounters a variety of challenges, from notorious outlaws to corrupt officials, utilizing his wits and marksmanship to maintain his cover and complete his missions.

Each episode presents Colt with different adversaries and moral dilemmas, reflecting the lawlessness and uncertainty of frontier life. He often finds unexpected allies among the townsfolk and is required to adjust his persona quickly to blend into unfamiliar environments. The clever narratives weave in historical elements of the Old West, emphasizing themes of justice, loyalty, and courage. Despite the dangers he faces, Colt remains dedicated to his dual role, balancing life as a seemingly ordinary gun seller and a stalwart defender of peace. His intricate investigations lead him through a series of suspense-filled escapades, where he must rely on quick thinking and resourcefulness, underscoring the complex nature of his covert operations. Through these adventures, he exemplifies the rugged individualism and pioneering spirit emblematic of the era.