New York City fireman Bill O'Connell is assigned to the Arson Sqaud with the job of apprehending the for-profit gang of arsonists who are spreading terror and loss of property, including human life. When his friend and battalion chief, J.P. Riley, is killed fighting one of the set fires, Bill declines the offered promotion to Riley's post in order to keep working against the arson gang. Riley's young son Tommy is left in charge of Bill and his fireman pal Tom Jones. Just as Bill is about to close the net on the gang leaders, Joan Lawrence, a young newspaper woman runs a story that puts Bill, whom she loves, on the spot (presumably) with the fire commissioner.