Robert Burton leads a solitary life in the desert as a gold prospector under the alias of Cameron. Burton is plagued by the demons of his past, but mainly the woman whom he wronged and disgraced. He encounters another man during his lonely sojourn through the desert, although he loathes to have anyone for company the two stay together. The older man discloses his identity as Jonas Warren, a man searching for his disgraced daughter who came West to start a new life when she found herself pregnant and the man she loved left her to disgrace. Burton confesses he is the man who shamed Nellie Warren, but he informs the aggrieved father that he had found Nellie and married her, thus giving their child a legitimate name. A truce is called, and Jonas forgives Burton. Unfortunately, the two men get taken by surprise by a sudden sandstorm. The two men take shelter under a rock shelf and Burton finds gold nuggets laying on the ground. Unfortunately, both men perish from the affects of the storm, but Burton is able to leave behind a note leaving half of the find to his daughter Nell Burton and the other half to whomever finds it. He also leaves his marriage certificate.
Years later Richard ‘Dick’ Gale comes to the border town of Casita. He has come West to prove to his father that he can be a man and stand on his own two feet. Dick meets an old friend, cavalry officer George Thorne, not long after his arrival. Thorne enlists Gale’s help in rescuing the woman he loves from the dangerous Mexican rebel leader Rojas. Gale’s friend has fallen in love with Mercedes Castañeda, a beautiful aristocrat who had to escape Mexico after Rojas killed her father and tried to kidnap her. Rojas pursues the woman relentlessly and has followed her to Casita. Thorne encountered Mercedes after she had crossed the border and they fell instantly in love with one another. Gale agrees to help Thorne and Mercedes escape Casita and the clutches of Rojas.
With the help of two cowboys Charlie Ladd and Jim Lash, Gale begins a fight in the bar of the hotel where Mercedes is staying and where Rojas is waiting to strike. He lunges on Rojas and knocks him out. In the ensuing chaos Gale escapes the building and meets up with Thorne and Mercedes. Thorne must leave Mercedes in the care of Gale since he must return to his regiment or face punishment. The two soon meet up with the cowboys Ladd and Lash, who after hearing Mercedes’s story agree to get her to safety. After a difficult night of travel the four make it to Tom Belding’s ranch in Forlorn River. Belding agrees to take Mercedes in and provide protection for her. He is not only a rancher but is a United States Immigration officer and is tasked with protecting the Mexican United States border. Belding hires Gale, Ladd and Lash as rangers whose job is to patrol the border. The men lead a rough life over the next few months due to Mexican rebels taking over Casita and crossing the border to steal horses and livestock.
Gale falls in love with Tom Belding’s stepdaughter Nell Burton. Her mother Nellie Warren Belding is worried about her daughter falling love with Gale since she does not want her to suffer the same fate as Nellie did at the hands of Robert Burton. The group is waiting for Thorne to join them, but as time passes he fails to arrive and Mercedes begins to grow ill with longing for her love. Nell decides to take matters into her own hands and sets out for the garrison in Casita to bring Thorne back to Mercedes. She discovers that he has been kidnapped by Rojas, who is trying to discover the location of Mercedes. Nell rallies the cavalry into rescuing Thorne and he is taken to Forlorn River to be reunited with the woman he loves. They are married as soon as he recovers from his traumas suffered at the hands of the rebel leader.
Unfortunately, their happiness is short-lived when Rojas discovers that Mercedes is at the Belding Ranch. He comes to profess his love for the young woman and assure Belding that he wishes only to marry her for he cannot live without her. Rojas gives Belding one day to think over what he has been told. In the interim Belding organizes everything necessary for Mercedes and Thorne to escape and make their way to Yuma. Gale, Lash, Ladd and the Yaqui Gale saved on one of his patrols from a group of Mexican rebels is tasked with seeing the couple safely through the perils of the desert. Yaqui is made the guide since the desert is the home of his people and he knows how to survive there. The group takes Belding’s best white horses and steals out into the night avoiding Rojas’s sentries.
The group intends to take one of the easier routes to Yuma, but due to the presence of rebel campfires all along their intended path Yaqui decides to take them through the Sonora Desert, a vast, desolate, dry wasteland of cactus and lava. The others fear this way, but Yaqui knows the desert and does not show any hesitation as he leads them onward. It is not long before they realize that Rojas has discovered the route they have taken and is not far behind him gaining ground quickly. Yaqui finds a perfect place to hide Mercedes and for the men to stage an ambush. Rojas soon arrives, and a gunfight ensues. Thorne and Ladd are wounded. Ladd continues to fight as he and Yaqui chase Rojas toward Mercedes’s hideout. Ladd falls, and Yaqui continues on alone. Rojas gets to the hideout where Mercedes tries to shoot him but is soon disarmed. The rebel leader struggles with her, trying to force himself upon her, but Yaqui attacks Rojas and they struggle. Yaqui kills Rojas and his body falls over the cliff to the abyss below.
After the fight has finished Gale runs to see who is injured and who is still alive. Thorne has a head injury but seems to be all right. Ladd is shot multiple times and Gale fears that he may not live long. Lash was shot in the leg, but the bone is not broken. Gale and Yaqui set up a camp and care for the wounded. Thorne develops blood poisoning but recovers. Lash’s wound begins to heal, and he is able to help take care of the others. Yaqui takes over the care of Ladd and uses herbs and roots to treat his wounds and the cowboy slowly begins to recover, but he is never able to recover his original stamina.
The group must stay at their camp until the rain begins since the desert is in the dry season and the waterholes are beginning to dry up. Gale and Yaqui keep them fed with mountain sheep and their waterhole is deep enough to sustain them for a long period of time. The rain finally arrives and the group head home to Forlorn River. They have been gone for months and the Beldings fear that they are dead. While they have been gone Tom Belding has been fighting against Ben Chase and his son Radford in order to keep his ranch. The father and son come into town and buy up all the land that Belding’s rangers had staked for their own. Unfortunately, they had not officially claimed the land, so the Chases are able to take it for themselves. Ben Chase also redirects the water so that Belding must buy it from him in order to water his own crops. These were all plans that Belding and Gale had developed for themselves, but the longer the group stays away the more Belding loses.
Radford Chase decides that he wants Nell Burton to be his wife, so he makes her life miserable trying to convince her to accept him. He even finds out that she may be illegitimate since there is not any proof that her mother and father were married. The men also threaten Nell’s mother with the information in order to sway her to force Nell to accept Radford. Mrs. Belding leaves to visit Peoria in order to escape the torment, but Nell refuses to leave since Gale may return any day. After Mrs. Belding’s departure Gale’s father, mother and sister come to Forlorn River in search of him. They are astonished to hear of Gale’s exploits and are amazed at what he has accomplished since he came West. They love Nell and happily accept her as Gale’s fiancée.
The Chase’s try one last effort to get Belding to give up his ranch by setting off an explosion that drives up his spring. Belding has reached the end of his patience, arranges to have Nell leave with the Gale’s to join her mother in Peoria. The rancher takes the two men away from the house and plans to shoot them but is saved from ruining his life by the return of Gale and the desert party. Upon their return the rangers are upset to discover their hopes and dreams of land and prosperity have disappeared due to the greed of the Chases. When Nell refuses to marry Gale due to her fear of Radford Chase telling everyone she is illegitimate, Gale decides to take care of the matter himself. He beats up Radford and warns Ben against spreading any further malicious gossip.
Nell still refuses to marry Gale since she loves his family and believes her illegitimacy will taint the family name. The Gale family assure her that they are happy to have her join their family no matter what. Nell does not give in and Gale is in despair since he has lost all of his hope for a happy future. Yaqui, however, convinces him to come with him into the desert. He takes Gale to the source of the Forlorn River, thus giving the young man the idea of how he can claim the land and divert the water for himself and his friends own purposes. Yaqui also finds gold nuggets laying on the ground of a nearby shelter and evidence of a large gold deposit. They also find the skeletons of two prospectors. They have left a note identifying themselves as Robert Burton and Jonas Warren, the long-lost father and grandfather of Nell Burton. Burton leaves the claim to his daughter Nell and to whomever finds it. He also leaves behind the marriage certificate that proves that he and Nellie Warren were married.
Gale and Yaqui return to the ranch with their good news. Gale plans to share the rewards of the gold deposit with all of his friends thus assuring them all a prosperous future. Nellie Belding returns to Forlorn River peaceful in the knowledge that her father has been found and can be buried. She also has the proof that Nell is indeed the legitimate child of Robert Burton. Nell and Gale marry and will spend part of the year back East and the rest of the year in Forlorn River. Yaqui says goodbye to the group and returns to his desert home.
