Franti, a street musician in New York's poor neighborhoods, has a daughter named Isola who sings while he plays the piano. His son Andrea is a burden on him and Isola, and is a member of the criminal "Red Galvin Gang." Nathan Marden, a wealthy banker, is drawn to Isola's voice, as is his son Charles. When Andrea continues to demand money, the gang threatens Franti with violence, and Franti is killed by a bomb. After Franti's death, Isola goes to vocal instructor David Mantz, who offers to train her, but she doesn't know Charles is interested. Mantz sends her to Paris to study, and she becomes a successful opera singer. At a dinner party in her honor, Charles becomes drunk and forces himself on her, leading her to move away. She returns to America for a performance at the Metro Opera House, where Charles tries to see her but is turned away. He eventually reunites with Isola after realizing she is his wife, but their happiness is interrupted by Andrea, who demands money and later robs and kills Nathan Marden Sr. Charles misunderstands Isola's involvement and leaves with their son, but returns after learning of Andrea's death.