17-year-old Jimmy Walker (Jack Nicholson, in his screen debut) is brutally beaten by Manny Cole (Brett Halsey) and two of his teen-age punk friends, Joey (Ralph Reed) and Al (James Fillmore), because Manny wants to move in on Jimmy's girl, Carole Fields (Carolyn Mitchell). Later, Jimmy shows up at the hangout of the teenage crowd to take Carole away, and challenges Manny to a fight. Manny's two buddies move in with brass knuckles, and one of them pulls a pistol, which falls to the ground in the scuffle. Jimmy picks it up and shoots Manny and Al. A police officer orders Jimmy to surrender, but he panics, thinking he killed the pair, and dives into a small storeroom, and holds Sam (Smoki Whitfield as Jordan "Smoki" Whitfield) and Mrs. Maxton (Barbara Knudston) and her small infant baby hostages. Police Lieutenant Porter (Myron Healey) and others plead with Jimmy to surrender and release the hostages, but the terrified Jimmy threatens Sam and Mrs. Maxton with death if they break out. A large crowd gathers and almost breaks through the police lines to storm the storeroom. Porter decides to use tear gas, with a rescue unit standing by to help Mrs. Maxton and her baby. Jimmy is captured, but because he shot in self-defense, looks forward to leniency...and on such things 45-years-and-counting careers are born.