Four Raptor clans shared a fragile peace on an ancient Earth—until a meteor strike devastated the Deathclaw Clan and cracked something open in the impact site. A strange life form called slime began flowing outward from the crater, spreading across the continent of Laurasia, mutating every species it touched and disrupting the ecology that all four clans depended on. The truce that follows is the only option: find the source of the slime, stop its spread, and prevent a mass extinction that will take everyone with it.