In The Railroad Forger and the Detectives, real estate agent Thomas H. Cone vanishes suddenly. At the same time, the Pinkerton Detective Agency’s Philadelphia branch, helmed by Mr. Linden, is hired by the Adams Express railroad company to investigate a draft forgery case. Two checks totaling more than $1,200 had been intercepted in the mail and falsely endorsed by none other than Mr. Thomas Cone!

Detective Allan Pinkerton and his associates, including the indispensable Mr. Bangs, travel to Troyville, Pennsylvania—a beautiful village known for its rural beauty and community of farmers—to investigate the robbery of the Howard Express Company. The thieves made off with nearly $15,000 and vanished. Pinkerton learns that two suspicious men had arrived in town the morning before the robbery, and he races to track them down and discover their connection, if any, to the robbery.

Upon receiving a telegram that reads, “First National Bank robbed, please come, or send at once” from Thomas Locke in Somerset, Michigan, Pinkerton sets off to investigate the crime. After journeying to the quaint town in a blizzard, the detective learns that $65,000 of treasury bonds, notes, and cash had disappeared from the bank’s vault overnight. Only one man knew the combination: the bank’s cashier, Mr. Norton. When Pinkerton’s subsequent examination of the crime scene reveals no signs of forced entry, it starts to look like Mr. Norton committed the crime.

Captain J. N. Sumner from Springfield, Massachusetts, hires Pinkerton to help solve a crime involving his sisters and the deed to a family farm. His younger sister Annie falls under the charms of a married man, Mr. Pattmore, who promises to marry Annie once his wife and her brother are out of the way. Captain Sumner possesses an opal ring with a stone that appears to foretell events. After suddenly falling violently ill, he becomes convinced his sister is trying to poison him to get his fortune and, more importantly, his ring.

Pinkerton travels to Atkinson, Mississippi, to investigate the murder of bank teller George Gordon and the theft of more than $130,000 in the City Bank of Atkinson. Atkinson appears at first to be no more than a quiet town of shopkeepers, laborers, and businessmen. But dark secrets lurk beneath the town’s Southern facade, and Pinkerton wastes no time in discovering them. Traveling under the guise of a cotton speculator, Pinkerton makes inquiries into the crime without drawing suspicion.