Robert Dunning commits suicide after he is ruined financially by a crafty Wall Street broker. Marcia Dunning vows revenge for her husband's death, and becomes a roulette operator in a gambling house where the broker's son often visits. She uses a magnetized finger ring to cheat the son, who then robs his father and causes the man's financial ruin. When Marcia learns that her daughter has secretly married the broker's son, she appeals to the gambling house partners to return the young man's losses. One partner refuses; another partner, who is in love with Marcia, stakes his share of the business against the others and loses. Marcia stakes herself against the winning partners, is prevented from using her magnet ring, but wins everything nevertheless. Marcia returns the stolen funds for the sake of her daughter, and then marries the partner who loves her.
—AFI