In 1898, Cassius ('The Cub') Delaney finds himself on an adventure straight out of a dime novel when he's given a try-out as a detective by Chicago's legendary Mahoney and Porter Investigative Agency. Mentored by Constantine Sherro, the agency's best (and worst) agent, the Cub finds himself up against a devious operative from the rival Pinkerton agency, and must choose what sort of a detective he will become.