A young woman marries into a corrupt oil family then falls for her husband's best friend.

In Texas in November 1956, drunken millionaire Kyle Hadley speeds through the town named after his father, oil tycoon Jasper Hadley, to their mansion home. Inside, a shot rings out and both Kyle and his wife, Lucy Moore Hadley, fall to the ground. Over one year earlier, Lucy is working for the Hadley Company in New York when she is noticed by Mitch Wayne, Kyle's best friend since childhood. Mitch invites Lucy to lunch with him and Kyle, who has flown from Texas with Mitch merely to have a sandwich at the "21" club. When Lucy expresses her distaste for the men's highly publicized playboy lifestyle, an impressed Mitch agrees with her assessment. She continues to earn Mitch's respect at the restaurant, while rejecting Kyle's advances. Her coldness motivates Kyle to invite her to fly to Miami on his private jet, and Lucy, overwhelmed by the adventure, agrees. Although uninvited, Mitch joins them on the plane, where Kyle finds himself willingly confessing his past to Lucy: As a child, troublemaker Kyle earned his father's contempt, while Mitch remained a bastion of good conduct and bravery. Believing he could never fill his father's shoes, Kyle turned to alcohol and a wanton lifestyle, as did his sister Marylee. Kyle's candor charms Lucy, but once they reach their Miami hotel, she realizes that the lavish gifts Kyle has heaped in her suite are payment for her company for the night, and leaves for the airport in secret. While Mitch revels in this confirmation of Lucy's virtue, Kyle races to her plane and begs her to allow him to court her properly, and confesses that he loves and wants to marry her. The next morning, at the same time that a saddened Mitch learns that the couple has eloped, Lucy discovers a pistol underneath her new husband's pillow. Five weeks later, Mitch is discussing business with Jasper when the newlyweds finally return from their whirlwind honeymoon. Based solely on Mitch's endorsement, Jasper receives Lucy warmly, and is even more heartened after she tells him that Kyle no longer drinks or carries a gun. Just then, bar owner Dan Willis calls Mitch and Kyle to rescue Marylee from sleeping with ruffian Roy Carter. At the bar, Kyle starts a fight with Roy, but after Roy knocks him out, Mitch steps in and beats up the thug. Marylee laughs bitterly as Kyle stumbles out, and later tells Mitch that she despises Kyle's weakness, and will never give up her childhood dream of marrying Mitch. After Mitch turns down her offer to be with him as wife or mistress, Marylee visits the river where they used to play, and weeps. In October, Kyle throws a party for his first wedding anniversary, where Marylee attempts once again to seduce Mitch, who is upstairs hiding from the festivities. Meanwhile, Kyle, concerned that Lucy has not become pregnant, questions their guest, physician Paul Cochrane, who reluctantly informs Kyle that he has "weak" sperm that may never impregnate Lucy. Devastated, Kyle resumes drinking, and the next night becomes so drunk at the country club that Lucy must put him to bed. Downstairs, just as Jasper tells Mitch that he blames himself for his children's shortcomings, the police bring home Marylee, who has spent the evening in a hotel with a gas-station attendant. Jasper struggles upstairs, but suffers a heart attack on the way and dies. By November, Kyle, who blames himself for his father's death, is still drinking and refuses to reveal his feelings to Lucy. Mitch tells Lucy that he is planning to take a job in Iran, and although she asks him to stay, he agrees only to drive her to Dr. Cochrane's. Marylee jealously watches them leave together and then lies to Kyle that the two are having an affair. When Mitch picks Lucy up later, he confesses his love, and Lucy kisses him passionately but reveals that she is pregnant and must stay with Kyle. That night, Lucy divulges her condition to Kyle, who wrongly suspects that the baby is Mitch's, and punches her. Mitch bursts into the room and threatens Kyle, who flees, and within hours Lucy miscarries. Kyle, meanwhile, goes to Dan's bar and announces that he must buy a gun to protect himself from Mitch, and then speeds home drunkenly. There, he finds his father's gun and aims it at Mitch, who calmly convinces Kyle that he has never touched Lucy, and informs him about his lost child. Drunk and confused, Kyle condemns Mitch for stealing the love of his father, sister and wife, and raises the gun. Marylee lunges for the gun in a desperate attempt to save Mitch, and the pistol discharges into Kyle's chest. He collapses, and hearing the gun go off, Lucy falls to the ground in grief. At the inquest for Kyle's death, Marylee tries to force Mitch to marry her by pointing out that, as his wife, she cannot present damning testimony against him. Mitch refuses, but at the trial, the servants and Dan bear witness that Mitch threatened to kill Kyle, and when Marylee takes the stand, she confirms the evidence. Stricken by her conscience, however, she finally reverses her story, stating that Kyle, who needed so much and had so little, was killed accidentally. Later, Marylee, dressed in a business suit and seated in her father's home office, cries as she watches Mitch and Lucy bid farewell to Hadley.