Anti-Catholic sentiment sweeps the nation, but in Troy, New York, a factory city at the confluence of the Hudson and Mohawk Rivers, U.S. Senator, “Boss” Ed Murphy runs all the municipal offices, the police department and even the schools. This charming Irish brewer, connected to the infamous Tammany Hall, retains his power by voting fraud, enlisting legions of young men with pistols to stuff the ballot box. Against this tide of lawlessness, a noble young Scotsman, Robert Ross, gathers a posse of his father’s millworkers to clean up graft and corruption by opposing Murphy’s pistol-packing ward heelers in a local election.
Bartholomew “Bat” Shea leads a gang of repeat voters to steal the election for saloonkeeper George Dunlop. He's seeking to raise himself up from the foundries and sweatshops that are killing his father. With his sidekick Jack McGough and a gang of repeat voters, he stuffs a dozen votes into various ballot boxes around the ward. When they clash with Ross’s posse, though, a riot breaks out and Robert Ross falls dead with a bullet in the back of the head.
Up rises attorney Frank Black, a self-proclaimed reformer and leader of the APA’s local chapter. He lionizes Ross as a martyr to the cause of liberty and mobilizes righteous vengeance among the elite. At a mass meeting called in a church and running on the old Abolitionist fervor, Black names Shea as the murderer, then harmonizes the testimony of witnesses and participates in the selection of the judge and the jurors to assure a conviction and the death sentence. But did Shea pull the fatal trigger?