Lucy Hegan, the proprietor of a settlement house for the poor, is engaged to Hugh Gordon, the head of a large pharmaceutical and chemical firm who, unknown to Lucy, is also the ringleader of a powerful drug and white slave operation in the Chinese quarter. While conducting an investigation into illicit drug traffic for his paper, newspaper reporter Allan Martin meets Lucy and falls in love with her. In the course of her work, Lucy has befriended reformed crook Monk Mullen and his mother, and when Monk learns that she is to marry Gordon, the ex-crook provides Allan with proof of Gordon's underworld drug trafficking. Armed with his information, Allan leads a raid on Gordon's headquarters, and in the ensuing battle, the drug king is killed by his henchman, Ling Choo Fang, thus freeing Lucy to marry her young reporter.