When Captain C.W. Langhorne, 4th United States Cavalry, takes a green lieutenant named Harry Bennett and a trio of Apache scouts on a hunting trip along the Rio Grande in the summer of 1916, he has no idea that their real quarry will turn out to be Mexican bandits and a kidnapped child. Although the rescue attempt goes sour, Langhorne captures a plan by extremists to ignite a bloodbath in the Border States. While U. S. authorities decide how to react to the threat, Langhorne and Bennett have their own troubles with the glory-hunting Major Philip Cobb back at Fort Bliss, including Bennett's unconventional romance with Cobb's young daughter. Finally assigned to stage a preemptive military strike against the plotters, Langhorne and Bennett find themselves battling not only Mexican revolutionaries, but also treacherous civilians, hostile terrain ...and Major Cobb.