During the Civil War, Bill Hickok is an officer in the Union Army, and is sent behind the Southern lines on a spying mission. His fumbling, but well-meaning aide, Jingles, does nothing to ensure the success of Hickok's mission.
The local townsfolk are furious when Wild Bill Hickok, who is serving as the U.S. Marshal based in a small Nebraska town, refuses to organize a posse to chase the remnants of the Quantrill gang after they attack the town. Bill is awaiting word of the outlaw's next raid from Jingles who has infiltrated the gang. The locals recognize the burly lawman as a member of the gang and try to lynch him before he can report to Hickok. Meanwhile McCanles, a local businessman, tries to keep Hickok off-balance while directing the gang to rustle valuable horses off nearby farms.
Wild Bill Hickok and Jingles are ordered to break up a gang of cattle rustlers. The agent for the Osage Indians' reservation has been murdered and the local cattlemen are accusing the tribe of stealing from their herds. Bill becomes suspicious of the man who volunteered to serve as a new Indian agent can me appointed.