Plot
In the summer of 1879, Lieutenant Colonel Kirby Yorke is posted on the Texas frontier in command of the 2nd U.S. Cavalry Regiment to defend settlers against attacks by marauding Apaches. Yorke has just captured the Apache's leader. Apaches have been using Mexico as a sanctuary from pursuit, and the regiment is suffering from a serious shortage of troops.
Yorke has been estranged from his wife and son for 15 years, after he set fire to his wife's family's plantation in the South under orders from his commanding officer during the Shenandoah Valley campaign of the American Civil War. Yorke's son, Trooper Jefferson (Jeff) Yorke, is one of 18 recruits sent to the regiment. After failing mathematics and flunking out of West Point, he immediately enlisted as a private in the Army. In a meeting with his father, Yorke informs him that he will receive no special treatment in the brutal way of life he has chosen; Jeff declares he wants none. Through his willingness to undergo any test or trial, Jeff befriends Travis Tyree and Daniel "Sandy" Boone, as well as the long-serving career troopers of the regiment. Tyree is on the run from the law for killing a man, but wants to wait to go to trial until after his sister's wedding. Yorke's estranged wife, Kathleen, arrives unexpectedly to buy the underage Jeff out of his enlistment. In a showdown with his mother, Jeff refuses her attempt to buy him out of the Army. The struggle over their son's future rekindles the romance the couple once felt for each other.
The Apaches attack the fort one night. Many of them are killed by the awakened troopers, but they succeed in freeing their leader. When Yorke's patrol reaches the Rio Grande, too late to capture the Apaches he was following, he meets a Mexican patrol. Yorke and the Mexican lieutenant in command exchange military courtesies, and both confirm that the US troops cannot cross into Mexico.
Yorke is visited by his former Civil War commander, Philip Sheridan, now Commanding General of the Military Division of the Missouri, the headquarters responsible for pacifying the Great Plains. Sheridan has decided to order Yorke to cross the Rio Grande into Mexico in pursuit of the Apaches and kill them all, an action with serious political implications. Sheridan promises that if Yorke draws a court-martial as a result of the orders Sheridan legally cannot give him, he will ensure that the members of the court will be his fellow soldiers from the Civil War. Yorke accepts the assignment.
Before Yorke leads his men toward Mexico, he sends the women and children to Ft. Bliss for safety, with an escort including Jeff. Jeff and Boone meet Tyree, who has gone Absent Without Leave to evade a Texas marshal who is looking for him. Tyree informs them that there are Apaches in the area. The Apaches attack the wagons and capture the one carrying the children and Corporal Bell's wife. The braves kill some of the escorting cavalry. While the remainder fends off the Apaches, Jeff returns to the fort for reinforcements. Tyree saves him from an Apache attack on the way.
The Second meets the survivors of the escort and follows the Apache raiders. They discover the burnt-out wagon and the body of Corporal Bell's wife, but there is no sign of the children. In the meantime, Tyree rejoins the regiment and tells them he trailed the Apaches to their hideout in Mexico. Working with Tyree, Yorke permits three troopers, Tyree, Boone, and Jeff, to infiltrate the village where the Apaches have taken the children. Then Yorke leads his regiment in an all-out attack. The cavalrymen rescue all of the children unharmed, though Colonel Yorke is wounded by an arrow that he orders Jeff to remove. He is taken back to the fort by his victorious troops, where Kathleen meets him and holds his hand as he is carried on a travois into the post.
After Colonel Yorke recovers, Troopers Tyree, Boone, Jeff, Corporal Bell, and Indian Scout Son of Many Mules are decorated. At the ceremony, when one of the Texas marshals reappears Trooper Tyree continues his run from the law, stealing General Sheridan's horse for the purpose. As the troops pass in review, the regimental band plays Dixie at the General's request, apparently to please Mrs. Yorke.
