Two young innocents are lured into the world of prostitution.

Mary and Lorna, the lovely daughters of Isaac Barton, an elderly inventor, work in a fashionable confectionary. Nice mannered procurer Bill Bradshaw lures Lorna to drink with him, after which he imprisons her in an abandoned house. When news of Lorna's supposed fall from grace reaches the shop, Mary's reputation is also tainted. She loses her job and is hired by Mr. Trubus, a renowned philanthropist who secretly leads a prosperous gang of white slavers, who prey on newly arrived immigrant girls. After Mary discovers that Bradshaw is working for Trubus, she and her sweetheart, police officer Larry Burke, who earlier rescued several girls from the same ring, gather evidence against Trubus using an invention of Barton that records his dealing onto a cylinder. After a rooftop chase, Bradshaw is shot and falls to his death, while Mary rescues Lorna. The ensuing scandal brings on the death of Trubus' wife and the insanity of his daughter.