Policeman Donald Patrick "Don" Dorgan is assigned to a tough neighborhood, known as "Little Hell," where his humanitarian approach to law enforcement wins the love and respect of the residents. Terry Rafferty, a young idler, falls in love with Effie Kugler, but despite his efforts at respectability and the entreaties of Officer Don, her father, Rudolph, refuses to permit their marriage. In a fit of despair, Terry turns to drink, resulting in his assault on a political boss and a prison sentence. Although Don is forced into retirement, he becomes known as "The Ghost Patrol," walking his beat and keeping the peace, unnoticed by his brutal replacement. Immediately after Terry is released from prison, Don brings Terry home and reunites him with Effie, who has chosen to defy her father. Meanwhile, Police Commissioner Manning learns of Don's activities and reinstates him as a police captain. At Christmas, Don persuades Rudolph to accept his daughter's marriage to Terry, and all ends happily.