In Los Angeles, the smalltime crook Roy Dillon is hit by a baseball bat in the stomach when he tries to swindle a bar attendant. His mother Lilly Dillon works in La Jolla for the powerful bookmaker Bobo Justus, who owns the Justus Amusement Company in Baltimore, placing bets to change the odds at the track but also stealing some money for her that she stashes in her Cadillac. When Lilly comes to Los Angeles to a horse race, she pays a visit to Roy after eight years without seeing each other, and she finds that he has an internal hemorrhage and sends him to the hospital, saving his life. When the experienced Lilly sees Roy's girlfriend, the slut and con artist Myra Langtry, she immediately finds that Myra is a roper. But the grieved Roy does not pay attention to his absent mother and decides to travel with Myra to La Jolla to spend a couple of days resting. Myra sooner finds that Roy lives of short-con grift and proposes him a great plan to rope tycoons; further she unravels Lilly's scheme with Bobo's money. When Roy turns Myra and her offer down, the greedy women set in motion a betrayal that brings tragic consequences to each player.