With the end of the North American Civil War, the manufacturers of repeating rifles find a profitable means of making money selling the weapons to the North American Indians, using the front man John Lattimer to sell the rifles to the Cheyenne. While traveling in a stagecoach with Calamity Jane and William “Buffalo Bill” Cody and his young wife Louisa Cody that want to settle down in Hays City managing a hotel, Wild Bill Hickok finds the guide Breezy wounded by arrows and telling that the Indians are attacking a fort using repeating rifles. Hickok meets Gen. George A. Custer that assigns Buffalo Bill to guide a troop with ammunition to help the fort. Meanwhile the Cheyenne kidnap Calamity Jane, forcing Hickok to expose himself to rescue her.

Passing through a small town, Joe is arrested for kidnapping. A lynch mob burns down the jail and Joe is believed killed. The incident has been captured on newsreel film and, for revenge, Joe urges his brothers to use the film to prove the mob guilty of his murder.

Immigrant radical Bartolomeo Romagna is falsely condemned and executed for a payroll robbery. Years later, his son Mio sets out to find the truth of the crime and to bring to account the gangster Trock Estrella.

While steaming from Honolulu to Los Angeles the owner of a prize racehorse headed for the Santa Anita Handicap is killed, apparently kicked to death by his stallion. Not so, deduces Charlie. Leter he exposes efforts to fix a race at the famous track.

While ostensibly on vacation with his wife and twelve children, famed detective Charlie Chan visits a circus at just the right time to become involved in the murder of one of the circus owners. Chan is prevailed upon to travel with the circus in hopes of discovering the killer before he, she - or it - strikes again.