A woman is abducted by those trafficking in young women, but her sister investigates and gets the evidence that will catch and convict them.
Mary Barton (Jane Gail) is engaged to Officer Burke (Matt Moore). She is late again to her job at the candy store, where she works with her sister Lorna Barton (Ethel Grandin). William Trubus (William Welsh) is the head of a citizens league, but his Go-Between (Howard Crampton) is making money for him by capturing and selling young women. He uses a dictaphone that enables a secretary in another room to get the information.
The look-out men are sent to welcome the immigrants, and they have the police arrest the brother of two Swedish girls. They put up the sign "Swedish Employment Agency," and Officer Burke asks about the new sign. They hand him money, but he breaks the sign, fights them, and pulls out his gun. He rescues the two Swedish sisters, and the police make arrests.
Lorna has been out drinking. Her sister Mary and her invalid father (William H. Turner) are worried because she has not come home. A man carries Lorna to a room, where a big woman guards her. Officer Burke asks the captain for the assignment to look for Lorna.
Mary loses her job because of Lorna's disgrace, but Mrs. Trubus (Millie Liston) likes Mary and gets her a job as the private secretary of the Go-Between. A newspaper reports that 50,000 girls disappear each year. Mary recognizes the abductor's voice. She follows the wire and sees the traffickers in the office next door. During lunch Mary tells Officer Burke. They use her father's invention for recording dictaphone sounds. They connect it in her office and hide it under the trash in a basket.
The next day Mary makes recordings on cylinders about the payments for girls. Mary takes the cylinders to the police captain. Police assemble and go off in cars. A high society man is planning to marry Alice Trubus (Irene Wallace). Lorna is still confined in the room, but she runs out. She is stopped downstairs while the police are sneaking up the fire-escape. From the roof Officer Burke directs the raid with a whistle. Police break in and rescue Lorna. The traffickers run and shoot at the police, who shoot back. One trafficker is killed, and the others are arrested. Police then capture the Go-Between in his office.
At the engagement party for his daughter Alice, police arrest William Trubus and show him the evidence that Mary got. The traffickers are in jail awaiting trial, but Trubus gets out on bail. Police protect him from a mob. When he gets home, Alice tells him that he killed her mother.
This pioneering feature was made for $5,700 and earned
$500,000. It's exposure of sex slavery was so controversial that
it was banned in most places. The drama also shows how new technology
can help catch criminals.