Protecting a woman aviator whose violent husband has already committed one murder, Isaac Bell of the Van Dorn Detective Agency oversees the woman's participation in a daring 1910 cross-country race, which is being sponsored by a wealthy newspaper publisher.

Investigating a series of attacks on the Southern Pacific Railroad's Cascades express lines, Detective Bell learns of the existence of an elusive saboteur who recruits and murders his own accomplices while engineering schemes of maximum havoc.

When a scientist he recently rescued from kidnappers is murdered, private investigator Isaac Bell discovers that a ruthless agent wants the scientist's secret new invention in order to exploit it to seize power for Germany.

When his boss is nearly killed while chasing a rum-running vessel at the height of the Prohibition era, Isaac Bell confronts a ruthless team of Bolshevik assassins and saboteurs intent on overthrowing the U.S. government.

Organizing a group of fellow law enforcers to dismantle an Italian mob that has spread throughout 1906 New York City, Detective Isaac Bell of the Van Dorn Agency begins to suspect that copycat criminals are using the gang's name to gain personal power.