Al Sieber arrives at a cowboy camp asking for Tom Horn, finds the scruffy young man trick roping, and hires him to be his assistant.

A young brave gives a message, which the "Talking Boy" Horn interprets: Geronimo warns "Man of Iron" Sieber to not chase him, or he will have to kill the scout.

Later, they meet a Cavalry patrol commanded by Lieutenant Lawton, which is en route to engage Geronimo, guided by two Apache whom Sieber recognizes as the chief's closest friends.

Instead of doing as ordered, Horn chases the Apache guides up to a hill, clubs them with his rifle, takes a vantage point, and shoots several braves, forcing them to retreat.

Later in the night, while they are drinking, Sieber tells stories about their soon-to-return commanding officer, his old friend Captain Emmet Crawford, expecting him to be a colonel already.

After a long search, they find an Apache camp in which there are only old men, women, and children: Sieber orders Free to burn it, which he does gladly.

Later, the troopers and the scouts are resting and eating together with the Apache prisoners; Lawton reproaches Horn for his respectful treatment of the Indians.

Sieber proposes Horn prospect mines and get rich, which means they dig a huge hole under the scorching sun, while drinking and chatting.

Sieber boasts he discovered a very productive copper mine; Horn rapidly realizes he sold it cheap and didn't get any wealth from it.

They see Lt. Lawton coming, and believe they are being called back to scouting, but the officer is only escorting Miss Ernestina Crawford, sister to the late Capt.

The next day is clear he is unable to continue, so he puts Horn in charge, advises him to kill himself if he gets captured by the Apache, and goes back to the fort, helped by Mr. Free.

Both Apache braves and cavalrymen die from exhaustion and skirmishes; they lose track of time to the point they don't know what month it is, and still cannot capture Geronimo.

While Sieber protests that sending desert people to swamp land means killing them, Horn runs toward the cage wagon in which a despondent Geronimo and other Apache are being hauled but he is overcome and knocked out by troopers.

A well-dressed, mustachioed Tom Horn arrives at a boarding house seeking a room; the landlady is Ernestina, who he doesn't recognize.

At the Club, Mr. John Noble offers Horn a large cup of brandy and introduces his wealthy and important companions.

He praises Horn's ascension, whereas he himself is now an itinerant lecturer who tells children about the Indian Wars, remarking that the incompetent Miles and Lawton became a politician and a general respectively.

That night, a very drunk Tom boasts to Ernestina he defied four men to a duel when he had no bullets left in his gun, certain they wouldn't dare to face him.

By day, Horn visits the ranch of the same four men from the saloon, sees their cattle has other people's brands and tells them they are going to be trialed as rustlers.

Back at the Club, Noble admits the cattlemen do want a bounty hunter, but as he is a lawyer, if ever Horn tells something about their deal he'll absolutely deny it.

After revealing to her a traumatic event of his past, Horn departs for a nocturnal incursion, in which he kills several rustlers, leaving their bodies lined in full view, with rocks under their heads.

Back at the jail, Smalley allows Ernestina to visit him; she warns Tom he is being railroaded, as the rustlers hate him and the cattlemen fear him telling people about who hired him.

The trial continues with the testimony of Deputy Snow, a stenographer who says he took accurate notes of the conversation Horn and Lefors had in the latter's room.

Later, from his cell's window, Horn watches the "Julian Gallows" being tested; Smalley apologetically informs him he has 16 hours left to live.

Tom screams in despair, but then he calms down, leaves the guns, and after a failed attempt at trick roping, goes back to his cell.

He gives Smalley the rope he had been braiding, asks Sieber to sing their favorite song "Life's Railway to Heaven" and climbs the gallows' steps firmly.

When Tom is tied up, he requests to be turned around to face the numerous attendance of newspapermen, sheriffs, marshalls, doctors, politicians, the judge and the prosecutor.

Crawford's death, Lt. Gatewood in Geronimo's surrender (1886), or like Jim McCloud, the inmate who started Horn's failed attempt at escape from prison.

Karen Black's character of Ernestina Crawford is fictitious, and replaces Horn's alleged girlfriend, the teacher Glendolene Kimmell.

David Carradine's characterization closely matches the historical Tom Horn both physically, in his cowboy skills like braiding ropes, as much in his drinking binges.

[16]: 238  Even if the script presents him as certainly innocent of the Nickell boy's murder (which is a matter of debate), it leaves clear the historical fact that Tom Horn had been hired as a killer and was both effective and a braggart in regards to that.