New York City. 1896. The heart of America's Gilded Age. When a young boy prostitute is found butchered on the unfinished Williamsburg Bridge, an alienist named Laszlo Kreizler (Daniel Brühl), a newspaper illustrator by the name of John Moore (Luke Evans), a secretary, Sara Howard (Dakota Fanning) and a police commissioner named Theodore Roosevelt (Brian Geraghty) begin an investigation outside the law to find the serial killer.

The investigation heats up as Sara (Dakota Fanning) gets her hands on a clue and Kreizler (Daniel Br?hl) tries to connect the evidence left behind by the serial killer. Tensions rise within the police department. Kreizler takes Moore (Luke Evans), SaraMarcus (Douglas Smith) and Lucius (Matthew Shear) to Delmonico's in New York and informs them they are going to be working together as a team to catch the killer.

Innovative evidence leads the team to discover a crucial element in the case has gone missing. Kreizler (Daniel Bruhl) and Moore (Luke Evans) interview a witness to find out what happened to Moore at the Brothel. Sara (Dakota Fanning) attempts to live in a world outside the investigation. Kreizler challenges them to look within themselves.

Kreizler and Sara discuss the capacity to kill. Moore goes on a date. Byrnes and Captain Connor keep an eye on a potential suspect. Roosevelt finds himself under public scrutiny.

The team learns more about the killer. Moore and Sara share an intimate moment. Kreizler seeks advice from an old mentor. Roosevelt takes action.

The team hatches a plan to catch the killer. Moore checks in on a friend. Kreizler faces his own self-doubt about the investigation. Roosevelt attends an event with the city's elite. Sara looks into Kreizler's past. Connor acts on impulse.