Retired fire captain Grandpop O'Neil conducts a rookie school, which includes his grandson Terry. The blaze in which Jim O'Neil, Terry's father, loses his life leads to an investigation and the discovery by Fire Chief Wallace that the building was flimsily erected by Corwin, a contractor favored in bidding for city jobs. When he protests the contractor's working on a new orphanage, the chief is removed by the town political boss. Terry discovers that the father of the girl he loves, Helen Corwin, is guilty of conspiring with the town boss and denounces him. A gigantic fire sweeps the city, and Terry is called into action with the antiquated horse-drawn equipment. He makes a valiant rescue of a child from a burning roof, though his brother, Joe, dies from the flames.