Christine Manning, daughter of oil company president Les Manning, returns from college with classmate Jane Hughes to spend the summer vacation at her widowed father's opulent home in Houston, Texas. Chris's mother died after a long illness when Chris was very young and although her father never talks about his late wife, he keeps a portrait of her in his home. Since his wife's death, Les has dedicated himself to becoming a very rich, ruthless oil tycoon. After Les confirms that there may be oil on the Diamond T Ranch, owned by brother and sister Jim and Katherine Tyler, he sends his chief assistant, Bob Johnson, to negotiate a land lease with the Tylers. Soon drilling crews arrive at the ranch and the first oil derrick is named "Christine # 1." Chris and Jane are invited to the Diamond T, and after being shown around the ranch, visit some of Houston's tourist attractions. When the well successfully produces oil, the Tylers host a barbecue to celebrate and, although Les does not attend, both Chris and Jane go to the party and are surprised to discover that Jim and Kate are active Christians. Later, when Jim and Les meet, Les tells him that he is glad he missed the party because he wants nothing to do with religion and adds that he does not want Chris "upset by supernatural tommy-rot." That night, after Les forbids Chris and Jane to return to the Tyler ranch as the Tylers are not the sort of people with whom he wants them to associate, he leaves for one of his many business appointments. After Jane leaves on a date with Jack Hillman, a co-worker of Bob's, Chris decides to find out where her father spends his evenings and phones Bob to take her to dinner where she asks him about her father. Bob reluctantly tells Chris that her father is a ruthless businessman whose God is gold-¿black gold-¿and that he is feared and hated by many people. Chris and Bob then visit several clubs, including a private one where the Manning name gains them entry. There Chris is dismayed to discover her father, accompanied by a hard-looking woman, gambling at a roulette wheel. After Les orders Bob to take Chris home immediately, Chris packs and leaves with Jane for the Tyler ranch, where Kate comforts them and tells Chris that she and Jim have been praying for her father since the first day they met him. Kate convinces Chris that she could be the one to lead her father to God by accepting Christ as her savior, which Chris does. The next morning, Les summons Bob to his office to ask where Chris is. When Les then fires Bob, Bob tells him that he quit the night before. After promising to blackball Bob in the oil business, Les then draws a gun from his desk drawer and threatens him. Jim enters, takes the gun from Les's hand and tells Bob to leave. Jim then lectures Les on his lifestyle and informs him that Chris and Jane are at his ranch. After Jim leaves, a distraught Les contemplates shooting himself, but is interrupted by a phone call from Chris saying that she will be returning the next day after taking Jane on a short outing aboard his yacht. Still distraught, Les goes home, gives his housekeeper the night off and turns on his television set. Switching from a weather forecast, Les comes upon a channel featuring evangelist Billy Graham and as he listens to Graham preach a sermon based on First Corinthians and the Ten Commandments, realizes that he has been a sinner in God's eyes and failed his late wife in many ways. Graham concludes by praying that many people watching him that night will be born again as they accept Jesus Christ as their personal savior. Les appears consoled and strengthened by the program's message. The next morning, Les receives news of an enormous explosion in Texas City where several of his oil storage tanks are located. As Chris and Jane were planning to sail from Texas City, he rushes there to look for them. Les finds Bob helping the injured and learns from him that Chris and Jane are safe and are working with a Red Cross team in a nearby church. When Les and Chris reunite, a reformed Les asks how God can use a wasted life like his and Chris assures him that God will guide him. After Chris returns to help the injured, Les realizes that he has not been in a church for twenty years, enters the sanctuary and stands in front of the altar.
