David Belkov, a newsboy born of foreign parents who live in "New York's crucible," the East Side, admires the late Theodore Roosevelt, but when he sees a poor family being evicted, he joins the Hogan Street anarchist group, of which his father's friends and his sweetheart Yolanda Kosloff, are members. The group plans to assassinate Judge Norton, who earlier condemned one of their comrades to the electric chair. After David witnesses the bravery of twelve-year-old Mary Hogan, who sings patriotic ditties to drown out the soap box orations of the anarchists, he prints leaflets to combat the anarchist views. Mary is killed trying to thwart the anarchists' plot, and David is caught and badly beaten. After government agents, thought to be converts, break up the gang, David arrives just in time to stop Yolanda, who is dancing at a celebration at Norton's home, from dropping a bomb. David is shot by the anarchist leader, but Yolanda, realizing her error, nurses him to health.
