Tycoon James Blanchard is sailing in his yacht and preparing to attend his daughter Barbara's wedding to Count Michael Montaine when he receives a radiogram from his ex-wife Vera. Vera informs him that the wedding has been moved up to the next day, and requests that Blanchard send $500,000 to Montaine, per her settlement with him. Blanchard realizes that Vera has bribed the count to marry Barbara in order to have a title in the family. Blanchard also realizes that Barbara is ignorant of Vera's scheme, and so sends a wire to her in Chicago, informing her of Vera's actions, and inviting her to join him in Los Angeles. Barbara receives the wire after the ceremony is completed and runs away. Vera, desperate to prevent Barbara from embarrassing her by divorcing Montaine, calls a press conference, announces that Barbara is mentally unbalanced, and swears out a warrant for her arrest. After Vera then sends Blanchard a wire that the couple are on their honeymoon, he angrily heads for Acapulco. Barbara reaches the outskirts of Chicago and, after attempting unsuccessfully to hitchhike, tricks Bob Reynolds into giving her a ride. Bob is reluctant to take her because he is part of a caravan that is driving new cars to the West Coast. It is against company rules to pick anyone up, and Bob fears that Willoughby Sproggs, the caravan's leader, will dismiss him. Bob's friends, Ted and Midge Dooley, convince Bob to give Barbara a ride to the next town, Ashton, and despite a close call when Sproggs inspects the cars, they reach Ashton without Barbara being found. There, Barbara and Bob part company while Rocks Hartley, a jewel thief traveling incognito with the caravan as Ray Webster, receives a telegram from his moll, Rita Laverne, saying that he must hide the stolen diamond necklace he is carrying. Hartley hides the necklace in Bob's car, and the caravan continues the next day. When Bob discovers Barbara hiding in his car, he threatens to leave her in the middle of nowhere. She sounds the emergency stop and, when the other drivers gather around, tells them that she is Bob's wife, whom he is trying to desert. Bob denies her accusations, but Sproggs's wife Cora insists that Bob take Barbara along. Back on Blanchard's yacht, he hears about the runaway heiress and steers for Los Angeles. Later that night, the caravan stops, and Bob and Barbara quarrel over who will sleep in the car. After Barbara storms outside, she is accosted by Hartley, but Bob comes to the rescue. Barbara spends the night in the car, where she finds the hidden necklace and concludes that Bob is a jewel thief. The next morning, while Barbara is advising a confused Bob to go straight, Midge reads a newspaper article about Rita and assumes that she is Barbara in disguise. She tells Bob and, when the caravan stops at a hotel, Bob is shocked to see Barbara being taken away by a policeman. Actually, Barbara has been arrested for participating in a crap game, and she is pleased when Bob helps her escape. As the couple are pursued by the police, they reveal their misconceptions about each other. They are also chased by Sproggs, Cora, Hartley, Ted and Midge, who are all arrested when the police catch Bob and Barbara. Blanchard arrives the next morning to get Barbara released from jail, but the astute father realizes that Bob and Barbara are in love. After telling Barbara that he will arrange for her annulment from Montaine, he leaves her and Bob locked in a cell together, and the couple embrace.
