A Mexican bandit, part of a gang led by his father, goes on a raid into the U.S. He falls for a beautiful woman and decides to leave his life of crime and settle down with her. Eventually his father and the gang come back for him, and he finds himself torn between his love for the woman and his loyalty to his father and his fellow gang members.

Azul, the adopted son of Ortega, a Mexican revolutionary bandit, is as cruel as Ortega's three real sons--Manuel, Xavier, and Antonio. During a raid on a Texas settlement in 1880, however, Azul kills Manuel to prevent him from raping Joanne, a young Texas woman. In the ensuing battle with the settlers, Antonio is killed and Azul wounded. Joanne and her father, Doc Morton, offer Azul refuge during his convalescence, and the two young people slowly come to trust each other. Azul, now called Blue, realizes that in killing Manuel he has severed his ties with the Mexicans, and he agrees to help Doc run his farm. After some reluctance on the part of Joanne's former suitor, Jess Parker, all of the settlers accept Blue, and he and Joanne fall in love. Meanwhile, Ortega, depressed by the loss of his adopted son, seeks him out; but their reunion quickly turns into a fight when Blue rejects the old man. His pride hurt, Ortega vows to return with a fighting force, and Blue reluctantly agrees to lead the Texas community against his foster father whom he still loves. The ambush organized by Blue to trap Ortega and his band at the Rio Grande is successful, and both Xavier and Ortega are killed. Feeling guilty for having betrayed his own people, Blue honors Ortega's last request that he be carried to the Mexican side of the river for burial. In so doing, Blue becomes a target for Carlos, a dying Mexican gunman who uses his last bullet to kill Blue. As the settlers pick up their dead, Joanne swims out to bring Blue's body back to Texas soil.