Reliquary (pendergast, #2)

The second novel in the Agent Pendergast series and a sequel to Relic, the story is set in New York City, 18 months after a creature known as Mbwun, the Museum Beast, terrorized the New York Museum of Natural History. The Beast, a reptilian predator addicted to a rare Amazonian plant, was killed during a catastrophic gala opening, but the trauma still haunts those involved.

The novel opens when police diver Snow discovers two headless human skeletons in the Humboldt Kill, a polluted canal on Manhattan's West Side. Lieutenant Vincent D'Agosta, a Homicide detective from the original Museum Beast case, oversees the recovery. One skeleton is identified as Pamela Wisher, a missing socialite. The second displays bone deformities unlike any known condition, and Chief Medical Examiner Dr. Simon Brambell finds teeth marks on both skeletons made before death.

D'Agosta brings the skeletons to the Museum's Forensic Anthropology lab, calling in Margo Green, an assistant curator of ethnopharmacology, and her former graduate adviser, Dr. Whitney Cadwalader Frock, a famous evolutionary biologist. Both recognize the teeth marks' resemblance to Mbwun's, though neither voices the connection. Frock agrees to assist, requesting Margo as his partner.

Journalist Bill Smithback, a New York Post crime reporter, writes about the Wisher murder, then is led underground to meet Mephisto, the self-proclaimed leader of an organized homeless community beneath Central Park. Mephisto reveals that beings he calls Wrinklers have been killing his people for a year, decapitating and eating them, and insists they murdered Pamela Wisher.

Sergeant Laura Hayward, a former Transit Police officer, brings D'Agosta evidence that seven recent murders among the underground homeless match the decapitation pattern. Her captain, the incompetent Jack Waxie, has ignored the cases. When D'Agosta's team explores the tunnels, they find a victim's severed head before being ambushed. The murders soon spread above ground when a man is killed and decapitated at Belvedere Castle in Central Park.

Brambell's forensic analysis confirms the teeth marks are consistent with a human bite, not Mbwun's. During his presentation, FBI Special Agent Pendergast, the investigator from the Museum Beast case, reappears and offers to assist. Police Chief Horlocker assigns Waxie to take over the case. Pendergast has already been underground in disguise and has learned of a group colonizing the deepest tunnels, a place called the Devil's Attic.

Two blows follow: Brambell is murdered, his throat cut, and the unidentified skeleton is identified as Gregory Kawakita, a former Museum curator and Frock's graduate student who helped identify Mbwun. Margo is devastated; Kawakita had tried to contact her months earlier, but she never returned his call.

Pendergast, disguised as a filthy homeless man, infiltrates the underground with D'Agosta. Through archival research and a retired city engineer, he discovers the Devil's Attic is actually the Astor Tunnels, a private railroad line built over a century ago by New York's wealthiest families some 30 stories underground, abandoned after flooding.

D'Agosta learns Kawakita operated a clandestine laboratory. Margo examines its burned ruins in the West Side railyards and identifies it as a genetics facility. In dried mud puddles that were once aquaria, she discovers roots and stems of Liliceae mbwunensis, the Mbwun plant, which was supposed to have been destroyed. She also finds fragments of a burned journal and evidence of genetic engineering.

Working alone, Margo has a breakthrough. The plant's reovirus, a type of virus capable of rewriting its host's DNA, exists in extraordinarily high concentrations. She realizes the Mbwun beast was not an animal but John Whittlesey, the scientist from the original Amazon expedition, transformed by ingesting the plant. Kawakita discovered this truth and manufactured a refined street drug called glaze, attempting to retain beneficial effects such as heightened senses and night vision while eliminating the deformities. His own skeleton proves his refinement was incomplete. The drug's users became the Wrinklers, deformed and feral creatures now living in the Astor Tunnels.

Events accelerate when Wrinklers ambush a stalled subway train, killing nine people. Pamela Wisher's mother, Anette Wisher, has organized a civic group called Take Back Our City to demand police action in response to her daughter's murder; the movement intensifies its pressure on the authorities. At an emergency meeting, Frock suggests flooding the creatures' lair by draining the Central Park Reservoir into the storm drains. Horlocker orders the operation for that night, overruling D'Agosta's objections.

Pendergast's solo reconnaissance into the Astor Tunnels reveals the Crystal Pavilion, a grand ruined waiting room with a hut of human skulls at its center, surrounded by ceremonial objects. Back at the Museum, Margo notices green patches on the Reservoir's surface. She and Pendergast confirm that Kawakita planted Liliceae mbwunensis in the Reservoir, now going to seed. If drained, the seeds will reach the tidal Hudson River, where saltwater will activate the reovirus, potentially contaminating the global marine ecosystem.

They race to stop the drainage but learn it cannot be reversed. Pendergast proposes sealing the tunnels with explosives: A Navy SEAL team will close the lowest spillway tunnels from below, while his team seals routes beneath the Bottleneck, a granite choke point through which all underground infrastructure in the area converges. The Reservoir is treated with thyoxin, an herbicide needing 24 to 48 hours to kill the plants.

A police operation to clear the underground homeless goes badly when tear gas drives hundreds to the surface, directly into Mrs. Wisher's march along Central Park South, triggering a riot. Underground, Waxie finds the drainage valves sabotaged and is killed when Wrinklers attack. Pendergast's team, guided by Mephisto, descends through the Bottleneck setting charges. Margo, who has realized that vitamin D is the mechanism by which sunlight kills the Wrinklers, joins them carrying squeeze bottles of the solution. They find Smithback, lost after witnessing Waxie's death, and continue to the Crystal Pavilion.

Detected and captured, the group is brought before the Wrinklers' leader: Dr. Frock. No longer wheelchair-bound, Frock walks freely; the drug restored his legs, lost to polio decades earlier. He explains that Kawakita came to him for help after the drug deformed Kawakita's body. Frock perfected the drug, eliminating deformities while retaining restorative properties including extended lifespan, but the final version magnified mental instability. His plan is to let the Reservoir drain, releasing the seeds to trigger a mass extinction he calls the Holocene Discontinuity, with himself as architect of a new evolutionary order. Margo confronts him, arguing that Frock killed Kawakita to prevent the former student from destroying the plants.

An unseen attack, possibly from surviving SEALs, sends magnesium flares into the Pavilion, blinding the light-sensitive Wrinklers. The prisoners break free. Mephisto detonates a stolen antipersonnel mine, killing himself and Frock. Margo drives back pursuers with her vitamin D solution, which burns their skin on contact. The charges detonate, sealing the tunnels. The group escapes through the flooding drainage system with scuba gear. Margo is separated by a pressure wave and swept through the underground, emerging battered but alive on the Humboldt Kill, where the original skeletons were found.

On the surface, the Reservoir overflows into Central Park, dispersing the rioters with a shallow flood. The group finds Margo the next morning. Pendergast expresses cautious hope that the collapsed tunnels contained the contaminated water.

In the epilogue, Hayward declines a promotion to complete her graduate studies, and Smithback publishes a bestselling account, donating half his earnings to homeless charities. One year later, Pendergast, D'Agosta, and Margo meet at a seafood restaurant. D'Agosta leaves with a relieved grin, suggesting the marine ecosystem was not contaminated.