Called out to her family’s derelict New Mexico ranch due to vandalism, NORA KELLY (early 30s), assistant professor of archaeology at the Santa Fe Institute, discovers her neighbor murdered, ritually mutilated.Then two mysterious, WOLF-LIKE MEN (SKINWALKERS), attack. Narrowly escaping with her life, Nora crashes her truck, only to discover a letter written by her father, PADRIAC, 16 years ago after he disappeared.

The letter reveals Padriac found the mythical Anasazi Indian city, QUIVIRA, somewhere in the red rock wilderness of Utah: Quivira, the legendary city of gold for which Cortez and his conquistadors searched relentlessly. The city’s discovery would be the biggest archaeological event of the century; and not only would it cement Nora’s career, but there’s a chance her father may still be alive.

Using state-of-the-art satellite scans of the landscape, Nora convinces eccentric PROFESSOR ERNEST GODDARD (early 60s), her wealthy mentor and the institute’s director, to fund an expedition. The only condition: Goddard gets to pick the team. Nora has no problem with this until he drops a bombshell—Nora will have to work with SLOANE GODDARD (30), the professor’s son and Nora’s former fiancé.

The remainder of the team are assembled: obsessive paleopathologist and MD ENRIQUE ARAGON (late 40s), his professional rival and bete noire, feisty and butch geochronologist ALICE BLACK (late 30s), satellite scan survey expert, techno-geek PETER HOLROYD (early 30s), irascible horse wrangler/cook ROSCOE SWIRE (early 50s), and acclaimed New York Times journalist WILLIAM SMITHBACK (late 30s).

With the flash-flood season fast approaching, the expedition departs via boat up Lake Powell. Unbeknownst to Nora, the group are being tracked by the Skinwalkers, evil Native American witches who derive their superhuman strength from psychotropic drugs.

Within two days, the expedition runs into the first of numerous life-threatening challenges when their boat’s route is blocked by flood debris. Swimming the horses into canyon entrance, Holroyd nearly drowns but is saved by Smithback. The following day, Nora narrowly escapes death while climbing a cliff face to reach a site where Holroyd can receive satellite signals.

The expedition’s situation soon goes from bad to worse: supplies are lost when a horse stumbles into quicksand, and fresh water is scarce in the narrow, steep, arid canyons. Then Holroyd contracts a mysterious, life-threatening illness (he has been poisoned in his sleep by the stalking Skinwalkers and the satellite communications system sabotaged). Nora suspects Sloane is responsible for the latter due to his resentment of her leadership, her rejection of his desire to rekindle their old relationship, and his awareness that she is attracted to the often irritating but charming and increasingly dependable Smithback.

Then the group face a life or death situation. Out of water, and too deep into the wilderness to turn back, the expedition must risk life and limb to venture over the dangerous terrain of The Devil’s Backbone, a crest of slippery slickrock. With no alternative, and Holroyd’s condition worsening, the team manage—barely: two horses and more supplies are lost, and Nora nearly falls to her death.

But the trek proves fruitful. First, they discover a sign left by Padriac Kelly, then unearth a hidden Anasazi road. Within a day, Nora and Smithback find Quivira—but the triumph is undermined by Holroyd’s death, and Aragon is convinced they are all at risk.

Quivira is more than any of them envisioned: a huge fortified pueblo complex built inside a huge cavern high into a sheer cliff face, and filled with turquoise and silver artifacts. But the specter of death haunts the city. When Aragon unearths a massive burial chamber filled with thousands of skeletons, he becomes convinced their lives are at risk. But Sloane and Black, who are having an affair (he “studied” under her at Princeton), believe the city hides an even greater treasure.

Having violated the Skinwalkers’ sacred ground, the members of the expedition are attacked in rapid succession: their horses are slaughtered and Swire murdered. But the team faces a greater threat in the shape of an immense thunderhead which forms over the nearby plateau and unleashes a flash-flood of biblical proportions, the like of which has never been seen on screen before.

The flood plain is decimated and a valley flooded by a rising torrent. Trapped inside the city, what will kill them first—professional rivalry and betrayal, the Skinwalkers, the natural elements…or Quivira’s dark, even deadlier secret?