Extinction

The Erebus Resort occupies a private valley in the Colorado Rockies, where Barrow, its creator, has built a safari-style park populated with animals resurrected from extinction. Using CRISPR gene-editing technology, Erebus's chief scientist, Marius Karman, has brought back woolly mammoths, giant ground sloths, and other megafauna from the Pleistocene, the geological epoch encompassing the last Ice Age. All the animals are genetically modified to remove aggression, and guests pay premium prices to observe them in a curated wilderness.

Olivia and Mark Gunnerson, newlyweds on a backcountry honeymoon trek, are camped at ten thousand feet with their guide, Stefan Dressel, after a day spent watching mammoths. Around nine p.m., something slashes the tent fly. Mark goes out to investigate and is attacked. Olivia follows and is struck in the back of the neck. Both vanish. Dressel reaches the tent within minutes and finds only two large pools of blood, dropped knives, and headlamps.

Frankie Cash, a forty-year-old detective newly promoted to agent in charge in the Colorado Bureau of Investigation (CBI) Major Crimes Division, helicopters in at dawn with her forensic team, including Detective Bart Romanski, head of CSI Forensic Services. She meets Sheriff Jim Colcord of Eagle County, a retired Army lieutenant colonel, and Andrew Maximilian, Erebus's Australian security director. Maximilian insists no animal could be responsible: Every de-extincted creature carries GPS and a video collar, and all predators have been removed from the valley.

The medical examiner estimates each bloodstain represents a fatal volume of blood that could only have been lost so quickly if the victims were decapitated. Romanski confirms at least six killers were involved. Bloodhounds track the scent to a mammoth stomping ground thick with dung, where the trail vanishes, a tactic Colcord recognizes as deliberate. Fingerprints from the scene match no law enforcement database.

Cash sets up a command post at the lodge. Mark's father, Rolf Gunnerson, a volatile tech billionaire, arrives drunk and erupts when told the victims could not have survived. He accuses Barrow of responsibility but refuses to explain, telling Cash only to investigate Barrow's business dealings and noting they both belong to Bohemian Grove, an exclusive annual retreat for powerful figures. Karman tours Cash through the lab complex, built into a retrofitted hard-rock mine. Cash and Colcord also visit a restored ghost town in the valley where director Slavomir Doyle is filming a Western with star Brock Ballou and a crew of thirty-two.

A drone search fails when Gunnerson lunges for the controls and crashes the drone. When Cash and pilot Lisa Stein hike to retrieve it, they find it gone and are surrounded by figures in homemade camouflage moving through the trees with animal-like stealth. Stein badly injures her ankle during their escape before a helicopter drives the attackers off. Cash confirms she saw at least eight people.

Colcord discovers that Erebus has a third mine, the Jackman, which Maximilian never mentioned. He photographs hand-drawn maps from Augustus Yearwood, an elderly prospector who confirms all three mines connect inside the mountains. The stolen drone later transmits a prerecorded video of a ceremony led by a tall man with a long blond braid and a birch-bark mask. He leads a group, including women and children, in a threatening chant and quotes Shakespeare's Twelfth Night. Inside a woven grass ornament hung around the altar, Romanski finds an old metal Monopoly shoe.

Barrow arrives for a voluntary interview, but Colcord brings in Gunnerson unannounced. Gunnerson confronts Barrow, accusing him of promising safety and causing his son's death. Neither man explains. The killers then murder Tom Thumb, a baby mammoth beloved by guests, within a thousand yards of the lodge, butchering it and taking choice cuts. Romanski discovers the killers mask their scent with mammoth dung and bile.

Cash's boss, Wallace McFaul, arrives and takes command, demoting Cash though the change is never made official. He refuses her requests to close the resort or call in the National Guard. Tracking dogs follow an unmasked trail from the mammoth killing to a rock shelter containing chopped, burnt, and gnawed human bones. Romanski confirms all six classic signs of cannibalism. Cash suspects the entire sequence is a deliberate message of terror.

Cash and Colcord enter the Jackman Mine through an unsealed entrance on Yearwood's maps and are ambushed. One guard is killed by a spear, another severely wounded. They return with a SWAT team, find the dead guard's body dismembered, and discover a steel door connecting the Jackman to the Erebus lab complex. Cash obtains a no-knock search warrant. During this period, a hundred pounds of dynamite is discovered stolen from Doyle's film set.

While McFaul holds a press conference, Cash, Colcord, Romanski, and CSI specialist Reno re-enter the mine. Romanski cuts through the steel door with a torch. Beyond it, they find an enormous underground space with an artificial sky, a stream, and a playground where a dozen children play. Romanski recognizes their broad faces, heavy brow ridges, and near-absent chins and identifies them as de-extincted Neanderthals.

Cash records video evidence, but Maximilian intercepts them. CEO Karla Raimundo orders them locked in a steel room equipped with a carbon monoxide nozzle, designed to make their deaths look like a mine accident. Gas begins hissing in. Then a massive explosion rocks the mountain: The Neanderthals have detonated the stolen dynamite, destroying the valley's power grid. The gas stops, the electronic lock disengages, and Cash pushes the door open.

The power failure frees all the Neanderthals. Cash's group hides as a torch-bearing mob streams past. From a catwalk, Cash sees the Neanderthals building a bonfire below, the severed heads of Maximilian and Raimundo mounted on poles, and the bound Barrow being led toward the flames. The group is spotted and sprints for the Jackman gate, escaping with a key Cash obtained earlier.

Outside, the valley is in chaos. The explosion has shattered the lodge's glass wall, and the structure is engulfed in fire. Neanderthals attack people in the meadow, beheading victims. McFaul hides in an aspen grove; Gunnerson attacks him for his gun, and McFaul shoots him. Air National Guard helicopters arrive, but Neanderthals fire seized weapons and bring one down. A Neanderthal kills McFaul with a spear. At the movie set, Doyle and Ballou flee in a van, but Neanderthals attack the vehicle and kill Ballou. Doyle escapes into the forest.

Karman, who also escaped through the mine, joins Cash's group as they climb toward thirteen-thousand-foot Espada Pass. He reveals the full truth: Erebus de-extincted Neanderthals to harvest genes for strength and speed, then inserted those genes into embryos carried by wealthy couples posing as honeymooners, charging twelve million dollars per baby. The parents never knew the enhancements were Neanderthal. Karman explains that Neanderthals are stronger and faster than humans but lack empathy, the trait that allowed Homo sapiens to cooperate in large groups and ultimately drive Neanderthals to extinction. Raised in comfort underground but kept ignorant of their true nature, the Neanderthals proved too clever. They pieced together the truth and, led by a charismatic young man named Joey, mounted a violent rebellion.

Joey, armed with a stolen AR-15, surrounds the group on the mountainside. Karman appeals to their shared history and offers Joey the full story of his origins: DNA from a Neanderthal artist buried in a painted cave in France. In exchange for releasing Cash and the others, Karman offers to join the Neanderthals and lead them over the pass into the vast Flat Tops Wilderness. Joey agrees. Cash's group descends toward arriving rescue helicopters. Above, a band of torchlight moves along the snowy ridge and disappears.

One month later, at a CBI debriefing, the toll is clear: Dozens are dead, including Barrow, Raimundo, Maximilian, McFaul, Gunnerson, and Ballou. Nine Neanderthals died fighting the Air National Guard, but roughly two dozen escaped with Karman and remain at large. The federal government has classified much of the information. Families whose babies received Neanderthal genes are being notified. Cash reflects that the Neanderthals can reproduce, might pass for human, and are loose in over a million acres of wilderness. The crisis is far from over.