The action takes place in the 1850s. Vans ride across the Texas prairie - this is moving from Louisiana to Texas to the bankrupt planter Woodley Poindexter. The son of Henry, the daughter of Louise and his nephew, a retired captain Cassius Kolhaun, are traveling with him. Suddenly they lose track - in front of them is a scorched prairie. The path to the caravan is indicated by a young rider in a Mexican costume. The caravan continues to move, but soon the horseman appears again, this time to save the settlers from the hurricane. He says his name is Maurice Gerald, or Maurice Mustanger, as he is a wild horse hunter. Louise at first sight falls in love with him.

Soon, in Casa del Corvo, where the Poindexters settled, a housewarming dinner party is due to take place. In the midst of the celebration, Maurice Mustanger appears with a herd of horses, which he caught by order of Poindexter. Among them, a mustang of rare mottled color stands out. Poindexter offers a large sum for him, but the mustanger refuses money and presents the mustang as a gift to Louise.

After a while, the commandant of Fort Indge, located not far from Casa del Corvo, arranges a return reception - a picnic on the prairie, during which mustang hunting is supposed. The conductor is Maurice. As soon as the picnic participants are on a halt, a herd of wild mares appears, and a speckled mare, after jumping after them, carries Louise to the prairie. Maurice fears that speckled, catching up herd, did not try to get rid of the rider, and rushes in pursuit. Soon he catches up with a girl, but they face a new danger - a herd of wild stallions, extremely aggressive at this time of year, jumps on them. Maurice and Louise have to flee, but they finally get rid of the pursuit only when the mustanger kills the leader with a well-aimed shot.

The heroes are left alone, and Maurice invites Louise to his cabin. The girl was pleasantly surprised to see books and other little things there, testifying to the master's education.

Cassius Colhoun, burning with jealousy, meanwhile, follows the footsteps of Maurice and Louise and finally meets them. They slowly ride alongside, and jealousy flares up in him with renewed vigor.

On the evening of the same day, men drink in the bar of the only hotel in the village of At Rest, which is held by German Franz Oberdofer. Calhoun offers a toast that is offensive to the Irish Maurice Gerald, while pushing him. In response, he splashes a glass of whiskey in his face to Colhoun. It is clear to everyone that the quarrel will end in a shootout.

Indeed, a duel takes place right here in the bar. Both participants are injured, but the Mustanger still manages to put a gun to Colhown's temple. He is forced to apologize.

Because of injuries, Calhoun and Maurice mustanger must observe bed rest, but Calhoun is surrounded by care, and Mustanger languishes in a wretched hotel. But soon baskets with provisions begin to come to him - these are the gifts of Isidora Covarubio de Los Llanos, whom he once saved from the hands of drunk Indians and who was in love with him. This becomes known to Louise, and, tormented by jealousy, she arranges a meeting with the Mustanger. During a meeting, a declaration of love takes place between them.

When Louise is once again going on a horse ride, her father forbids her to ride on the pretext that the Comanches have gone on the warpath. The girl surprisingly easily agrees and begins to get involved in archery - with the help of arrows she exchanges letters with Maurice Mustanger.

The exchange of letters is followed by secret night meetings in the courtyard of the estate. Cassius Kolhaun, who wants to use this as an excuse to get rid of the Mustanger with the hands of Henry Poindexter, is witnessing one of these meetings. A quarrel occurs between Henry and Maurice, but Louise persuades her brother to catch up with the Mustanger and apologize to him.

The infuriated Kolhoun is trying to set a certain Miguel Diaz on Maurice, who has his own accounts with the Irishman because of Isidora, but he turns out to be dead drunk. Then Calhoun himself goes after Maurice and Henry.

The next day, it turns out that Henry was missing. Suddenly, at the gate of the estate, his horse appears with traces of gore. They suspect that the young man was attacked by Comanches. Fort officers and planters gather in search.

Suddenly, the innkeeper appears. He says that the night before the Mustanger paid the bill and moved out. Soon Henry Poyndekster appeared at the hotel. Finding out in which direction the Mustanger had gone, he galloped after him.

The search squad rides through the forest clearing, when suddenly, against the backdrop of the setting sun, a rider without a head appears before the eyes of the assembled. The squad is trying to follow in its footsteps, but the tracks are lost in the "chalk prairie." The search was decided to be postponed until morning, and the major, the commandant of the fort, reports evidence found by tracker Spengler, excluding the involvement of the Indians. Suspicion of murder falls on Maurice Gerald, and everyone decides to go to his hut in the morning.

At this time, a hunter Zebulon (Zeb) Stump, a friend of Maurice, comes to Casa del Corvo. Louise tells him the rumors about her brother’s death and the involvement of Maurice Gerald. At her request, the hunter goes to the Mustanger to save him from lynching.

When the hunter is in the hut, the dog Tara comes running with Maurice's business card tied to the collar. It says with blood where he can be found. Zeb Stump appears just in time to save a wounded friend from the jaguar. Meanwhile, Louise from the roof of the estate sees a rider who looks like Maurice. After jumping after him, she finds Isidora's note to Maurice in the forest. Jealousy breaks out in the girl, and she decides, contrary to decency, to go to her lover to check her suspicions. In the Mustanger's hut, she meets Isidora. At the sight of a rival, she leaves the hut.

Thanks to Isidore, the search squad easily finds the Mustanger's home in which Woodley Poindexter finds his daughter. He sends her home. And on time, since the audience is ready to lynch the alleged killer, mainly due to the false testimony of Colhoun. She manages to postpone the execution for a while, but passions flare up with renewed vigor, and the unconscious mustangers are again ready to pull the bitch. This time, Zeb Stump rescues him, demanding a fair trial. Maurice Gerald is taken to guardhouse in Fort Indge.

Zeb Stump follows the trail of the drama. During the search, he manages to see a headless horseman at close range, and he is convinced that this is Henry Poindexter.

While awaiting trial, Calhoun asks Uncle Louise for his hand - he is his debtor and is unlikely to be able to refuse. But Louise does not want to hear about it. Then at the trial, Calhoun talks about her secret meeting with the Mustanger and about the quarrel of the latter with Henry. Louise is forced to admit that this is so.

From the story of Maurice in court it becomes known that after a quarrel they met Henry in the forest, reconciled and exchanged cloaks and hats as a sign of friendship. Henry left, and Maurice decided to spend the night in the forest. Suddenly, a shot woke him, but he did not attach any importance to him and again fell asleep, and in the morning he found Henry's corpse with his head cut off. To deliver it to his relatives, the corpse had to be planted in the saddle of a Mustang belonging to Maurice, since Henry's horse did not want to carry this gloomy burden. The mustanger himself mounted Henry's horse, but did not pick up the reins, so he could not control it when he carried it. As a result of a frantic jump, the Mustanger hit his head on a bough and flew off his horse.

At this moment, Zeb Stump appears, leading Colhoun and the headless horseman with him. He saw how Kolhoun tried to catch the rider in order to get rid of evidence, and he makes it clear in court that Kolhoun is the killer. The proof is a bullet extracted from the corpse with the initials of Kolhoun and a letter addressed to him, which he used as a wad. Streaked Kolhoun tries to escape, but Maurice Mustanger catches him.

Calhoun confesses to the murder, which he committed by mistake: he aimed at the Mustanger, not knowing that he had changed clothes with his cousin. But before hearing the verdict, Kolhoun shoots at the Mustanger, who is saved from death by the medallion presented by Louise. In desperation, Calhoun fires a bullet in his forehead.

It turns out that Maurice Gerald is the owner of a great fortune. He marries Louise and redeems from the heir of Colchown (it turns out he had a son) Casa del Corvo. Servant Felim O’Neill and Zeb Stump, who delivers game to the table, happily live with them. Ten years later, Maurice and Louise already have six children.

Soon after the wedding of Maurice and Louise, Miguel Diaz kills Isidora out of jealousy, for which he is hung on the very first bitch.