The heart-stopping opening scene is set by the docks as the Hornets, led by Frankie, rumble with their rival gang the Dukes, as soon as a foghorn sounds. The Hornets grab one of the Dukes as a prisoner and after roughing him up Lenny pulls a zip-gun on him and threatens revenge for the Dukes jumping him, which was the cause of the fight. Frankie’s upstairs neighbor, Mr. McAllister, passes by the alley and reports the incident to the police. They arrest Lenny. When Frankie next sees McAllister, he calls him out and threatens him for snitching. McAllister slaps him hard across the face, and Frankie singles out fellow gang members, the chicken-hearted 15-year-old Baby (Sal Mineo) and the psychotic Lou (Mark Rydell), to help him bump off McAllister, the rest of the gang turns their back on Frankie and refuses to commit a murder. The dedicated bachelor Wagner, who works overtime without pay and receives a salary of only $75 a week at the neighborhood Duane Settlement House, realizes something is up with the gang and does his best to try and talk with an unresponsive Frankie in order to save him. While Wagner is talking with Frankie’s innocent 10-year-old brother Richie (Peter J. Votrian), the kid blurts out he overheard Frankie say he was going to kill someone. Trying to talk to Frankie’s hardworking waitress mom with no success, the social worker again confronts Frankie for a personal chat. Wagner tells Frankie that he’s angry at the world because his uncaring father ran away from the family when he was eight without ever saying goodbye to him and ever since then he’s had a chip on his shoulder. But this doesn’t stop Frankie from killing McAllister, it takes his brother to do that.