Kay Boylan convinces her younger brother Johnny not to quit school and go to work to support their impoverished family. Mrs. Boylan does not favor Kay's engagement to Paul Wilson, who is also a friend of Johnny, but she is willing to wheedle money out of him until Kay prevents it. Johnny's unemployed father, Jim, is coerced by his wife into taking a job at a factory whose workers are on strike and comes home injured one day, having been attacked by "scabs" when he tried to aid a striker. Although innocent, Jim is arrested for killing a policeman during the melee, and the other boys in school taunt Johnny over the family misfortune. When Jim is found guilty of murder, Mrs. Boylan grows despondent, while Paul stands by the family. Kay is fired from her job, and tells Paul she fears she will drag him into their unpleasant situation. The family is forced to leave their apartment and move to the slums. The thieving boys of this rough part of town are impressed that Johnny's father is considered a murderer. When Johnny starts to sell newspapers, he takes over another boy's corner, but is accepted when he beats one of the gang in a fight. Unfortunately, Johnny begins to spend all of his time with these toughs, ignoring his family and Paul. Kay, meanwhile, takes a job in a burlesque show and refuses to reunite with Paul. One day Rita Belle Warren, a girl from the old neighborhood who loves Johnny, comes to visit him. The gang disrupts a broadcast of the Young America Upward and Onward League and are joined by Cyril Gerrard, a young, pretentious thrill seeker of means. Later Jim's court appeal is denied and the judge rejects Johnny's attempt to plead for his father. In reprisal, Johnny throws a rock through his window and is sent to a detention home, from which the gang releases him. Johnny returns home to interrupt Kay and Paul as they are making up, then runs away. Johnny and the gang begin to live as small-time criminals but Johnny sends his ill-gotten money home and learns of the coming wedding of Paul and Kay. Cyril, now claiming he is a criminologist, turns his friends in to the police. Johnny escapes with one other boy, who is killed when police later surround them. After Kay convinces Johnny to surrender, the gang is sentenced to the Grant School for Boys. The judge has sympathy for Johnny, despite the more serious nature of his crimes and, moved by Kay and Rita Belle's affection for him, decides to send him to the school as well. There, Rita Belle, Paul, Kay and Mrs. Boylan visit Johnny.