Town ne'er-do-well Brett Conway finds out that a couple who moved near North Fork and soon fell sick are actually ill with highly contagious and potentially fatal yellow fever. Knowing that Lucas was the person who initially discovered the couple, Conway threatens to spread the news of their condition to the entire town, thereby causing a panic, unless Lucas buys his silence.

In order to rob the stage which is carrying $20,000.00 in cash, an unarmed outlaw informs Lucas, who is riding shotgun, that his son's life is in mortal danger if he doesn't hand over the money.