During the Mexican-American War of 1846-48, many Irish soldiers in the U.S. Army deserted to join their Catholic brothers fighting for Mexico. The Mexican Army assigned them to el Batallón de San Patricio—the Saint Patrick's Battalion. After the American victory, the deserters were rounded up, court-martialed and shot. Now the sons and grandsons of those Irishmen and their Mexican wives are avenging the executions by launching hit-and-run attacks across the border into Texas towns. Captain Mack Hawkins and his Kiowa-Comanche Scout Detachment are sent to the area to put a stop to the raids. The captain and his second-in-command, Lieutenant Ludlow Dooley, quickly discover that the mixture of Irish and Mexican blood produces ferocious and incredibly brave fighting men. It's a sure bet there'll be hell to pay before the last bullet is fired.

Captain Mack Hawkins and Lieutenant Ludlow Dooley with their Kiowa-Comanche detachment of U.S. Scouts are dispatched to the Arizona Territory. An Indian prophet by the name of Veratodo is preaching war to the Apache tribes living on the reservation in the Tierra Brava Desert. His sermons announce the coming of a messiah by the name of Alzaron who can summon slain Indian warriors back to life. Veratodo promises there will be thousands reappearing on earth to massacre all whites that exist. Hawkins and Ludlow lead the detachment into the hinterlands to track down and kill or capture the followers of this charismatic messiah. Unfortunately, nobody bothers to inform the unit that they will be fighting fanatical warriors who have no fear of death since they expect to be resurrected by Alzaron.

Captain Mack Hawkins, Lieutenant Ludlow Dooley and the Kiowa-Comanche Detachment of Indian Scouts are sent on a hazardous assignment up into the Rocky Mountains of Montana. Their orders are to protect railroad surveyors coming under fire from hidden snipers. But when the detachment arrives, they find themselves caught in a deadly crossfire. Mysterious threats and baffling situations abound that are intertwined with gun battles and ambushes in the mountainous crags and forests of the Rockies. To further complicate matters, a revolution by the Métis—a people of mixed French and Indian blood—against the Canadian government unexpectedly involves Hawkins and his men.