Mona, a beautiful Indian girl, and daughter of the Chief, had given all her passionate love to Ortega, a brave. The old chief takes the attachment with stoic indifference. The young Indian couple are wrapped up in each other until the white man comes. Ortega and two warriors are hunting. They see the prairie schooner without the sign of life. They approach with Indian caution and find a man, a woman and a child lying within. The woman and child had gone to join their maker. The man has a spark of life left. They work over him and Ortega fetches water from the life saving spring. They take the man back to the Indian camp and nurse him back to life. Mona finds two books in the wagon and the man surprises Ortega and Mona pouring over them. Ortega is fascinated. The pictures of Eastern activity and invention fill his brain, and Mona's heart sinks and she tries to get rid of the man and the books. The man goes, grateful and somewhat amused, and the spirit of civilization having entered Ortega's soul, he follows and enters a college. Mona, even with his promise to return constantly in her mind, broods and her primitive hatred for the whites takes possession of her. Ortega does well. His brain is abnormal, and in due time he writes a brilliant thesis. His roommate sees it and determines to make it his own. He and another youth plot and so arrange matters that Ortega is accused of theft. He hotly denies the charge, but seeing he is not believed, shakes off the white man's shackles and starts back to his tribe and Mona. In the meantime, the girl's character has undergone a change and believing Ortega has gone from her life, awaits a chance to wreak her vengeance upon the whites. The squaws avoid her and even the medicine man is afraid of her. She often rides out alone with her faithful horse, and one day sees two prospectors taking a drink in the spring where the hated white man was revived. She gets her quiver of arrows and dips the arrowheads in rattlesnake poison, and going to the spring, contaminates the water with the arrowheads. She awaits some definite result and sees, with fiendish satisfaction, a man approach the spring garbed in the white man's apparel. He drinks, staggers and falls. She goes to gloat over her work and finds her lover, Ortega, dying. Turning, she sees her horse drinking from the fatal spring. The faithful animal falls beside her and, bereft of friends and reason, the wretched girl leans down, and smiling at the green water, drinks.