In 1875, notorious outlaw Apache Jack flees into the Arizona desert after killing the bride of Manuel Lopez. Sheriff Bill Cummings sets out on Apache Jack's trail with a posse comprised of Manuel Lopez, who seeks to avenge his wife's murder; Westerners Rayburn and Chic Lyman; an Easterner named Mulford; frontiersman Kier; cowboy Billy Sweet; Eaton, an Englishman; and two prospectors, Cluff and Garth. Deep in the Arizona wastelands, the party discovers the body of an advance scout who was killed by Apache Jack. When the posse arrives at an oasis in a narrow wash, the men quench their thirst in the water, but are startled by the sight of several skeletons near the watering hole. While Cluff and Garth find indications of a rich silver deposit in the area, the posse sets up camp. Eaton is appointed to stand guard over the horses at night, but at daybreak the Sheriff awakens to find him, his horse and Cluff and Garth missing. No sooner are the men found at an adjoining wash, however, than Cluff is killed by a bullet fired by an unseen Apache sharpshooter on the ridge. Certain that they are surrounded by Apaches, the men play cards to determine who will be sent to get help. Garth and Billy are pressed into the dangerous mission, but before they go, a horse carrying Eaton's corpse rides in, reminding them of the Apaches' deadliness. The endless wait for help to arrive proves too much for Lopez, who takes off on a mad search for his dead wife. While attempting to stop Lopez, Kier is stabbed. The Sheriff, Mulford, and Rayburn are the only men left alive after the wounded Kier dies, and Lyman is shot from his horse by an Apache. Desperate, the three men devise a plan to create a diversion to allow two of them to flee unnoticed by the Apaches. Rayburn goes up the wash, while the Sheriff and Mulford hide in the rocks, but he is soon shot by the indians, who approach the watering hole thinking that they have killed off the last remaining man. As Apache Jack examines the graves of the murdered posse, the Sheriff and Mulford shoot and kill the outlaw and several indians. Believing that they have eliminated the Apache threats, the Sheriff and Mulford emerge, only to be fired upon by a wounded indian, who kills Mulford. The Sheriff, the sole survivor of the ambush, shoots the wounded Apache and is soon rescued by a passing cavalry party.