It's a sixty-five million year old cold case that's heating up fast.... The most complete Tyrannosaurus rex skeleton ever found surfaces in Sheriff Walt Longmire's jurisdiction, and it appears to be a windfall for the High Plains Dinosaur Museum. Then Danny Lone Elk, the Cheyenne rancher on whose property the remains were discovered, turns up dead. With millions of dollars at stake, the skeleton is claimed by Danny's family, the tribe, and the federal government. Longmire is determined to find out who would benefit from Danny's death.