Tom Mix trades horses for cars. Tom Higgins meets Patricia O'Malley whose father is a car manufacturer. O'Malley is hoping to land a contract with a Japanese firm, if only his car wins the Los Angeles-Phoenix auto race. Hap enters, but O'Malley's driver, Luther McCabe causes the race to be lost. Higgins discovers that McCabe is in league with O'Malley's competition, so for the next race, in Fresno, he takes over when McCabe drops out and wins the race.
Henry Baird, a young newspaperman with a second-hand car but little money, decides to raffle off the car at a county picnic, so that he can take out his sweetheart, Mabel Darrow, the daughter of a wealthy businessman. However, as soon as Henry gets the money, his tailor demands that he pay off his debt. Also, youngsters set the car on fire before he can give to the winner, Joseph Plant, whose wife Evelyn was formerly Henry's sweetheart.
Illiterate Blue Ridge Mountain girl Madge Brierly falls in love with vacationing Blue Grass aristocrat Frank Layson, when he stops Horace Holten from defrauding her of her coal-rich lands. For revenge, Holten tells moonshiner Joe Lorey, who loves Madge, that Frank is a revenue officer. After Madge rescues Frank from Joe's attack, they go to Frank's home, where he teaches her reading and writing, and she rescues his racehorse, Queen Bess, from a fire set by Holten. Because Frank has nearly all of his family's money riding on the big Kentucky race, Holten gets Frank's jockey drunk. Madge, discovering this, disguises herself and rides Queen Bess to victory. She leaves for home unnoticed, and comes across the Night Riders chasing Lorey. After she persuades them that Holten killed her father years earlier, and was responsible for Lorey's attack, they chase Holten who falls from a mountain and dies. Years later, Madge's and Frank's children play at feuding.
After her father is killed by an outlaw, Dolores marries Peter. While they're at sea in the Arctic, Dolores meets the ship's captain, who is the man who killed her father. The captain causes an 'accident' to happen to Peter, so Dolores is all alone and defenceless as they drop anchor in a remote harbour.
A young engineer, Tom Morley, is building a railroad through Imperial Valley. Tom's father also wants the job, and tries to persuade his son to give up the work, but Tom refuses. Tom falls for a society girl named Alice Hale, who marries him to bring prestige to her family. Initially, Alice plots against Tom, but Tom wins her over and they work together to defeat those who are plotting to destroy Tom's work.
A man falls in love with a piano player and tries to woo her. A passerby hears a maid's music, fancies he's found his true love, and chats her up. Her boyfriend arrives for his music lesson and jealously dismisses the interloper, who swipes a grinder's organ (and monkey) to help him serenade the maid. Later he follows the boyfriend to a residence hotel and plants a bomb in the man's piano. The organ-grinder is gunning for the thief, and soon the piano, bomb, monkey, thief, and pistol-packing grinder are rolling down the road to the delight of maid and lover. It's ka-boom for some and a kiss for others.
A happy young couple become engaged, and soon afterwards they are married. But after their marriage, the husband begins to stay out carousing with his friends, leaving his wife at home with her mother. Then, when the three of them go to the opera together, the husband spots one of his friends in another box. Soon the domestic difficulties reach their peak.
Denton, an anthropologist of note, meets by accident a new neighbor, an attractive girl, whose father insists upon her marriage to a man whom he favors because of his wealth. Denton and the girl are mutually attracted and to Denton comes a vague but haunting belief that they have met before. Worn out by overstudy, he becomes seriously ill with rain fever and the mind pictures he has of his fair neighbor fade into a vision of a prehistoric existence, where he wanders as a stone age savage, meets and loves the girl of his heart, who also lives in that strange world. There also is the conflict between wealth and poverty, the father's choice opposed to the daughter's. The prehistoric Denton finally wins out after struggling with a savage rival and wild beasts as well. Just so the modern Denton finally conquers over his modem rival.