The Mexican civil war had been grinding on for so long that the United States resorted to using private contractors—mercenaries—to prop up the failing Mexican Army. One of the many things the Mexican Army failed to protect was Pangaea, the famed animal park in remote northeast Mexico, a symbol of rampant capitalism. All the creatures inside were killed at the time. At least, that's what was reported.

For his estranged son Michael's high school graduation, hotel mogul Roger Rudd splurged on a rare and expensive hunting trip in Mexico, hoping it would bring them closer. To get there, they hitched a ride down on one of the contractors' helicopters, picking up Tina Echevarria, a beautiful and feisty Mexican graduate student, along the way.

But when the helicopter crashes in the Sierra Madre Oriental mountains, its combat-seasoned contractor crew, led by Irishman Seamus O'Malley, will have to lead the disparate group on a cross-country scramble, trying not only to evade guerilla fighters, but also the prolific and savage offspring of the artificially created animals once filling Pangaea. Animals thought to be eradicated a generation before, when Pangaea's walls were breached. Animals called theropods by the park officials . . . but known to the rest of world as dinosaurs.