Dora Miller and her father together with Juan, a young half-breed, live peacefully at their ranch along the Rio Grande. Juan is in love with Dora and she is not averse to him. One morning while the little family is seated at breakfast, shots are heard outside. A party of U.S. soldiers has been attacked by Mexican troops and retreating as they fight, finally taking refuge in the Miller homestead. The doors and windows are barricaded and a sharp fight ensues. Juan, the half-breed, refuses at first to fire against the people whose blood runs in his veins, but at last infuriated by the sight of a wound received by Dora, he grabs the rifle and begins firing furiously. He is thus engaged as the Mexican troops break into the house and is captured by them and locked in an upstairs room.