A mysterious young woman deplanes in Albuquerque, New Mexico, travels north to the wilderness area near the village of Pecos, and assassinates a man, only to find out later that the killing was a mistake, and that she must return to find and eliminate her true target, a woman. Special Agents of the FBI and a female under-cover agent of the shadowy Third Directorate of the CIA set out to find the assassin, her target, and the plot behind it. The federal agents discover that the key lies with an employee of the sprawling Rio Grande Laboratories who has been compromised by Russian FSB agents, and that two powerful, secretive factors, one Russian, the other U.S.-based, are vying for technical details of the labs' secret "Geronimo Queen" energy project. After a second assassination and a search for a unique weapon used by the assassin, the trail leads to a remote mansion in the mountains of Montana.