A young man goes missing while searching for treasure in Skeleton Canyon in Cochise County, Arizona. Kit and Swifty are called in by a relative after local law enforcement fails to come up with any clue to the missing man's whereabouts or what happened to him. Skeleton Canyon is located just north of the Mexican border. The east end of the canyon is in New Mexico and the west end is in Arizona. For hundreds of years the canyon was a thoroughfare for Mexicans and the Apache. It has been the scene for a massacre of all the members of Mexican burro train carrying silver bullion. It was where the Apache ambushed Troop D of the Fourth U S Cavalry, killing three troopers, burning their wagons and supplies and driving off forty horses and mules. It was where old man Clanton of the Clanton gang of Tombstone was murdered. It was also the site of Geronimo's surrender to General Nelson Miles in 1886.

The canyon has a dark and bloody history and is a rugged and desolate spot locals fear and tend to avoid.

Kit and Swifty find themselves in danger as they encounter bands of illegals sneaking into the U.S., cartel drug smugglers, and others who have become experts at not being seen or found in one of the most dangerous places in the United States.