Anthony Fairhaven, head of the Moegen-Fairhaven Group, purchased land at the corner of Catherine Street and Henry Street in lower Manhattan and tore down the apartment buildings currently there to build a new 65-story residential tower.
During the construction process, Fairhaven seemed unusually interested in the site and visited regularly. While excavating the foundation for the new tower, construction workers broke into an old brick tunnel. Inside the tunnel they found the skeletons of 36 people. The NYPD were called in to investigate, and the case attracted the interest of Special Agent Aloysius Pendergast of the FBI. Pendergast summoned archaeologist Nora Kelly of the New York Museum of Natural History and the two visited the site. The bodies appeared to have been from mostly young people, and had been dumped haphazardly into niches in the walls of the tunnel.
Pendergast and Kelly quickly dated the site to the late 1870s and early 1880s, when the plot had been the site of J.C. Shottum's Cabinet of Curiosities and Natural Productions. The bodies were taken away quickly and buried at Gates of Heaven Cemetery and construction was resumed. Kelly and her boyfriend, newspaper reporter Bill Smithback, snuck back into the site and recovered a dress belonging to a young girl, Mary Greene.
Kelly and Pendergast investigated the history of Shottum's Cabinet of Curiosities and found that Shottum himself had died in a fire at the building in 1881. In the museum's archives they discovered a letter from Shottum to his colleague Tinbury McFadden. In the letter, Shottum revealed his suspicions about a man named Enoch Leng, another scientist who had a laboratory on the third floor of the Cabinet. Shottum, suspicious after seeing blood drip through the floor of Leng's laboratory, let himself in using a master key and read Leng's journal. The journal contained Leng's experiment notes and revealed that he had been dissecting live human beings and extracting part of the spinal cord, the cauda equina, to create a serum that he hoped would extend his life.
Smithback obtained a copy of the letter and wrote a story about it in the New York Times. Shortly afterwards, a series of killings began to occur in Manhattan. The police speculated that the murderer was a copycat killer, inspired by Enoch Leng's story. The press dubbed the suspect, a man in a derby hat and black coat, "the Surgeon".
As Pendergast continued to investigate the case, he came to believe that the Surgeon was Leng himself, and that he had succeeded in prolonging his life since the late 1880s. He, Nora Kelly, and Smithback eventually located Leng's other laboratory and finally his home at 891 Riverside Drive. There they discovered that Pendergast was partly right. Leng had succeeded and was alive until shortly before the discovery of the tunnel. Furthermore, Pendergast determined that Leng was actually his distant relative, Antoine Leng Pendergast.
Anthony Fairhaven, obsessed with cheating death, had discovered Leng's research and had independently tracked him to Riverside Drive. He tortured the old man to death, hoping to make him reveal his secret formula, but Leng confessed nothing. Fairhaven, a regular visitor to the museum archives, somehow discovered Leng's association with the Shottum's Cabinet of Curiosities and bought the site.
Fairhaven found Leng's experiment notebook in the rubble of his old lab and studied the skeletons removed from the site before their burial. He began killing people as he tried to replicate Leng's experiments. Also Fairhaven adopted the man's dress and persona.
Pendergast and Nora Kelly found Fairhaven at Riverside Drive mansion. He and Pendergast fought and Pendergast lured him into Leng's innermost laboratory, where his final experiments were stored. In a room full of antique arms and armor, Fairhaven handled several weapons as he considered how to kill the wounded Pendergast. Unbeknownst to him, Leng had coated everything in the room with extremely deadly contact poisons and Fairhaven died a horrible death.
Pendergast, unwilling to reveal the contents of Leng's home to the world, did not notify the police. He bricked up Fairhaven's body behind the basement wall. The residential tower at Catherine Street was presumably completed and Surgeon killings went officially unsolved.