An ex-Confederate Army officer (Richard Boone) named Jim Lassiter, who has been revenging himself against Apache Indians who have massacred his family, recovers a stolen U.S. Army repeating rifle from some Apaches he has killed. The U.S. Army arrests him, offering him his freedom if he leads a small clandestine scouting unit into Mexico consisting of an Army Captain (Stuart Whitman), a Buffalo Soldier sergeant (Jim Brown), a knife wielding Mexican prisoner (Tony Franciosa), and later an Apache woman warrior (Wende Wagner).