The Millionaire Kid is young Tommy Neville whose wealthy parents, Thomas and Gloria Neville are preparing to fight it out in divorce court.Tommy runs away from home. The private detective assigned to watch him tells Mrs. Neville he has been kidnapped. She immediately suspects her husband. Meanwhile, Tommy is selling newspapers in another city. He is attacked by a bully, and is rescued by gangster Terry Mallon and his daughter Kitty. Unaware of his identity, they take him to their beach home. Reporter Breezy Benson is sent to interview Mrs. Neville about the divorce, and is fired when she won't talk to him. He meets Kitty at the beach and is intrigued by her. He meets her father, who is curious but not suspicious as news of the alleged kidnapping has not been reported.
Ballard's trail jumpers attack the Wyatt Company wagon train, killing young John's parents and kidnaping his brother, Jim. In post-Civil War California, John Wyatt, now a man, pulls together a vigilante posse, The Singing Riders, who all ride white horses, dress alike, and ride the trails singing and rounding up outlaw gangs. Meanwhile, John is ever on the lookout for the gang that murdered his parents As a youngster John Wyatt saw his parents killed and his brother kidnapped. On a wagon train heading West he meets his brother who is now a spy for the gang which originally did the dirty work. He and his brother both fall for Mary Gordon When Ballard and his men attack the Wyatt wagon train, they kill all except two young brothers. Twelve years later one brother John has organized a vigilante group. The other brother Jim is now part of Ballard's gang and the two are destined to meet again
The story deals with the college rivalry of a piccolo player and an All-American halfback on the football team who both love the same co-ed. After graduation they carry their their feud and collegiate ideas over into the department store business.