A psychologist, along with his team of a secretary, a police commissioner and a newspaper illustrator, hunt down a serial killer who is targeting boy prostitutes in New York City in 1896.

Dr. Kreizler attempts to link the evidence left behind at the crime scene by the killer. Plus, Sara gets her hands on a clue and tensions rise within the police department.

Innovative evidence leads the team to uncover a critical element in the investigation has gone missing. Plus, Moore and Kreizler interview a witness to try and figure out what happened to Moore while at the brothel.

Captain Connor and Byrnes keep an eye on a potential witness, while Moore goes on a date. Plus, Roosevelt comes under scrutiny from the public, and Sara and Kreizler discuss the capacity to kill.

While continuing their investigation, the team start ti discover more about the killer and their motives. Plus, Kreizler seeks out an old mentor for advice, and Sara and Moore share an intimate moment.

The team devise a plan to catch the killer and Connor makes an impulse decision. Plus, Kreizler must learn to face his own self-doubt about the investigation, and Roosevelt attends an event with the elite personalities in the city.