Laura Henderson, an orphan, is brought up by her aunt, Mary Sherman, who keeps a boarding house. Among the boarders is Angelo Angelini, an Italian violinist. Laura is infatuated with the handsome Angelo, who loves her, and they are engaged to be married. Angelo betrays the girl, and later leaves her, with the explanation that he is to make a western concert tour. A month later, the poor girl receives a letter from Angelo telling her that he has returned to Italy, where he has a wife and child. Later a daughter is born to Laura, who is named Ruth. Unable to obtain employment in her own town, the unfortunate mother abandons her child to the care of her Aunt Mary, and goes to New York. Ill and weak from hunger, the poor young mother is picked up in the street by Reverend Henry Bradley, who takes her to his home. Dr. Bradley and his mother offer Laura a home, and work as secretary to the minister. Later Dr. Bradley falls in love with Laura, and asks her to become his wife. Laura accepts his proposal, and she marries Dr. Bradley, without telling him that she has an illegitimate child, and she secretly sends money to her aunt for the support of her child, Ruth. Nineteen years later, Dr. Bradley is now chaplain of the City Prison of New York. They have a daughter, Aline, who is about to be engaged to Walter Jordon, who comes from one of the finest families in New York. Ruth, now a girl of 20 years, believes that Mary is her mother. One day she happens to find out through a letter that Laura sent to Mary, that she is not Mary's daughter. Ruth forces Mary to tell her who and where her mother is, and at last Mary confesses the truth. Ruth determines to go to New York and seek her mother. Meanwhile Angelo has returned to America and, under the assumed name of Angell, lives in New York with his son, Tony. The boy refuses to work and becomes one of the vilest of all human creatures, a "cadet." Tony pretends to rescue Ruth from an attack by one of his pals, prepared by himself, and the poor girl, believing him to be a decent man, accompanies him to a restaurant. Then Tony takes Ruth to his own room, telling her it is the home of his "highly respectable aunt." A letter sent by Tony to an accomplice, offering to sell the girl to him for white slavery in New Orleans, is seen by Ruth, who realizes her perilous position. She tries to escape from the room. Tony threatens her with a pistol, and in the struggle which follows Tony is shot dead. Angelo enters the room just as his son has been shot. The poor girl is arrested and taken to prison, where she meets Chaplain Bradley and tells him her sad story. Unaware that it is his own wife's daughter, he is helping, the chaplain takes Mrs. Sherman to visit Ruth in prison. Mrs. Sherman is confronted with a terrible situation. Laura's legitimate child, Aline, is celebrating her engagement to Walter Jordon in the magnificent home of the latter's parents. Mrs. Sherman decides it is her duty to the unfortunate Ruth to acquaint her mother with the terrible facts. Laura while celebrating the betrothal of her younger daughter, learns that the child of her first love languishes in prison charged with murder. The unfortunate mother becomes temporarily deranged. Aline, the younger daughter, on learning of her mother's disgrace, is heartbroken, breaks off the engagement with Walter, and later her dead body is found by her father and lover, the second victim of the Sins of the Parents. At the trial of Ruth for the killing of Tony, Angelo appears as a witness. The father is about to speak the words that will condemn his own daughter to the electric chair for the killing of his son, when a commotion in the rear of the court room causes him to be silent. Laura, the mother of the prisoner, has escaped from her nurse and has forced her way into the court room. She recognizes Angelo, the man who betrayed her 22 years ago. and who is now about to condemn his own daughter. Angelo now learns, for the first time, that his own daughter killed his son; he suffers keenly, refuses to speak. The half-demented mother is led out of the court room by her husband and court officers in a hysterical condition. The jury brings in a verdict of acquittal on the ground of self-defense. Ruth is free, but alone in a great city. Dr. Bradley takes Ruth into his home to her mother. Laura, realizing the noble stand of the minister, and feeling that she is unworthy of her husband she has deceived, decides to leave the house with her daughter, Ruth, in hope that the disgrace she brought upon her husband will be forgotten, but Bradley resigns as minister and insists upon Laura staying where he will stay. He folds both mother and daughter in his arms, gives them his blessing, thanks the Lord that to him it has been given the honor to help two suffering souls into the light. Angelo, suffering as the result of his youthful sins, decides to commit suicide, but has not the courage to do so. Bradley receives a reply from the board of directors of his congregation, stating that they have looked into the misfortune that has befallen upon his family and they congratulate him for his noble act, and ask him to remain with them as their minister. Bradley shows the letter to his wife. Laura, heartbroken, falls on her knees and begs forgiveness of her husband.