When a local rancher's body is discovered in Tuzigoot National Monument, Doug and Jill Fletcher are dispatched to investigate the suspicious death. Horseshoe prints where the body was found point the investigation toward the dozens of local ranches and trail ride companies.

The clues lead the Fletchers into Cottonwood, a nearby tourist town with a blossoming wine tasting industry. It quickly becomes apparent that the victim was a bed-hopping cowboy, who has left behind a string of scorned women and angry husbands.

While riding along the Verde River in search of clues, Doug and Jill are befriended by Gunner, a young cowboy who'd been injured in a rodeo accident. Socially inept and somewhat slow, Gunner sees things that others overlook. His daily rides around Tuzigoot made him a reluctant witness to much of what happened following the murder.

Despite slowly developing confidence in his horsemanship, Doug is forced to ride "Lightning" when their prime suspect flees on horseback. He and Lightning follow, as Jill gallops off in pursuit of their murder suspect. The chase turns into a scene from a Wild West movie when the fleeing cowboy fires his six-shooter at his pursuers.