Set in New York City in 1896, a journalist and an investigative team assembled by police Commissioner Teddy Roosevelt try to solve a series of murders; based on the novel by Caleb Carr.
In 1896, a psychologist, a journalist and a secretary begin an investigation outside the law to find a serial killer targeting young male prostitutes in New York City.
The investigation heats up as Sara gets her hands on a clue, while Kreizler tries to connect the evidence left behind by the killer. Tensions rise within the police department.
Evidence leads the team to discover a crucial element in the case has gone missing. Kreizler and Moore interview a witness to find out what happened to Moore at the brothel.
Captain Connor and Byrnes keep an eye on a potential witness, while Moore goes on a date. Roosevelt comes under scrutiny from the public.
While continuing their investigation, the team start to discover more about the killer and their motives. Kreizler seeks out an old mentor for advice.
The team hatches a plan to catch the killer, Moore checks in on a friend, and Kreizler faces his own self-doubt about the investigation.
Kreizler and Moore follow a lead, while Sara visits a hospital and is forced to confront her past. Detectives Marcus and Lucius Isaacson work on a clue.
Kreizler and Moore's investigation takes them to Washington, DC. While in a hell-bent pursuit of the truth, Sara loses her way and goes rogue.
Kreizler mourns the loss of a friend, and Cyrus is determined to seek revenge against Connor. Sara and the team head to the Census Bureau, where they get a lead on their suspect's location.
As time starts to slip through their hands, the team finally closes in on the killer. Kreizler confronts the demons of his past, and Connor decides to take matters into his own hands.