Plot
Lilly Dillon is a veteran con artist. She works for Bobo Justus, a mob bookmaker, making large cash bets at race tracks to lower the odds of longshots. On her way to La Jolla for a race, Lilly stops in Los Angeles to visit her son, Roy, a small-time hustler she has not seen in eight years. She finds him in pain and bleeding internally after being caught pulling a petty scam and beaten by one of his marks. When medical assistance arrives, Lilly threatens to have the doctor killed by Bobo if her son dies.
At the hospital, Lilly meets and takes an instant dislike to Roy's girlfriend, Myra Langtry, who is slightly older than him. Lilly urges Roy to quit the grifting life, as his con nearly got him killed. Because she leaves late for La Jolla, she misses a race where the winner pays 70 to 1. For this, Bobo punches Lilly and insinuates he will beat her with oranges wrapped in a towel, causing permanent internal damage, but he burns her hand with a cigar instead. Myra, like Roy and Lilly, is also a con artist, often using her sexuality as a means of getting what she wants, including paying her landord with sex.
Upon leaving the hospital, Roy takes Myra to La Jolla for the weekend. On the train, Myra eyes him conning a group of sailors in a rigged dice game. Myra reveals to Roy that she is also a grifter and is looking for a new partner in a long con. She describes her association with Cole, her old partner, and how they took advantage of wealthy marks in business cons. Roy, who insists on working only short-term cons, resists the proposition, fearing Myra may try to dupe him. Seeing Lilly's power over Roy, Myra accuses him of having an incestuous interest in her. Infuriated, Roy breaks off their relationship. Thirsty for revenge, Myra finds out Lilly has been skimming the proceeds from Bobo over the years and stashing the money in the trunk of her car. Myra leaks this information to Bobo, and Lilly is warned by a friend and flees. Myra follows her to a remote motel, intending to kill her and steal the money for herself. She gains entry to Lilly's room and strangles her in her sleep.
Later, Roy is called by the Phoenix police to identify a body believed to be Lilly's, found in the motel room with her face disfigured by a gunshot wound. Though he tells them it is Lilly, Roy notices the body lacks the cigar burn that he had noticed earlier. He returns home to find Lilly has broken in to steal his money. Lilly reveals she shot Myra in self-defense at the motel while Myra was trying to strangle her. She arranged the scene so it would appear as though Myra's body was hers and that she had committed suicide. When Roy refuses to let Lilly take his money, she desperately pleads with, then attempts to seduce him, even claiming that he is not really her son. Roy, disgusted, rejects her, causing Lilly to angrily swing a briefcase at Roy just as he is taking a drink of water, shattering the glass and sending shards into his neck, which cause him to bleed to death. Sobbing over him, Lilly gathers the money into the briefcase, but by the time she boards the elevator she is completely calm and showing no emotion. Lilly leaves the hotel and disappears into the night.