Joseph Smith bids farewell to Nauvoo as he, his brother Hyrum, and a group of other men head out for Carthage. On the way they meet Captain Dunn and his militia, who arrest the two brothers. The militia revel in this victory for the mobs.
In Carthage, Robert Smith is the justice of the peace and the captain of another militia called the Carthage Greys. He and a member of his militia, the mobocrat, see Joseph and Hyrum coming into town and greet them with blatant threats of murder. The Carthage Greys surround them and taunt them, with Satan watching in the background.
Joseph and Hyrum are brought to the court of Robert Smith where a mock trial takes place and they are pronounced guilty of treason. They are then brought to the Carthage jail.
Three good friends of Joseph, John Taylor, Dan Jones, and Willard Richards, choose to follow Joseph to the jail, where they plan to stay with him, even to death. Meanwhile Robert Smith and the Carthage Greys meet with Governor Ford to come up with a sinister plan on how to deal with the whole situation.
Dan Jones overhears the guards talking about the plan and leaves the jail to warn Governor Ford. When the Governor seems unconcerned Dan condemns him and hurries back to the jail, but is not allowed inside.
Governor Ford marches with several militia groups into Nauvoo as a show of force. He leaves behind a number of Carthage Grey soldiers to guard the jail. Dan Jones complains loudly to the Governor over the choice of guards, but the Governor reassures him that Joseph will be protected.
On the way, the Carthage Greys are eager to plunder Nauvoo, but are disbanded when the Governor overhears this. They return to Carthage to take part in the murder.
The jailkeeper senses something is amiss, and suggests that Joseph and his colleagues move to the basement cell for safety, which they promise to do after supper. Joseph asks Willard Richards if he will follow him there, and Willard says he will follow him anywhere, and will even die in his place. John Taylor sings "A Poor Wayfaring Man of Grief" at the request of Joseph, which event is hinted at in the music.
Meanwhile the wives of the men involved in all this are home praying for their husbands. Jane Law praises her husband for saving the church, while Emma expresses her outrage at the traitorous apostates.
All throughout Carthage, men are gathering into a vicious mob who arm themselves, blacken their faces for disguise, and descend upon the jail. A gunfight ensues, in which the guards only make a show of resistance. In minutes the jail is surrounded and swarming with mobocrats. Hyrum is shot and cries out, falling into Joseph's arms. Joseph, attempting to draw the fire from his other friends, retreats to the window. He is shot three times and cries out, then falls out of the window to his death.