Marion Atwell, a compulsive gambler who loses a large sum of money at bridge, becomes increasingly indebted to Henri Duval, a shill for a gang of thieves and murderers who prey on the idle rich. Duval offers to free Marion of all her debts if she will gain his gang's admittance to Mrs. Jonathan's Jewel Ball, a social occasion at which all of the guests wear their best gems. Marion notifies the detectives instead, and Duval and his men are arrested. Marion tells her pathetic story to the guests at the ball and is forgiven by friend and family alike.