A rough fist-fight breaks out. During the savage brawl, townspeople gather around to watch. One of the bystanders asks: "What happened? What are they fighting about?" Jimmy replies: "Don't know. Don't know themselves probably." One of the local townspeople, Charlie Thomas (Hugh Sanders), derides Police Chief Bleeker for not arresting "these jerks." He is no better than the troublesome bikers when he suggests the solution is to take the law into his own hands and "bust a few heads."

Charlie: Let's stop this. I've seen hoodlums like this before. If you don't get tough with them the minute they get out of line, you're sunk. (To Bleeker) You are the cop, aren't ya? If you can't boot these jerks out, there's plenty of us that can, even if we have to bust a few heads.
Bleeker: That won't help matters.

During the fight, both brawlers crash through the window of a store that sells formal wear - an interesting contrast in appearances.

When Charlie tries to drive his honking car through the rumble and knocks over one of the gang's bikes (and shakes up one of Chino's gang members), the angry mob pulls the driver out of his car and turns his car over. Bleeker, feeling pressured into doing something, decides to arrest both Charlie and Chino, but then is persuaded by town merchants to single out Chino. As the police chief starts to take Chino to jail, Johnny asks why the driver wasn't arrested too. At that point, Bleeker asks Johnny to do him a favor and leave town.

I've given you a couple of chances. I-I don't know what you're after....I'm in a spot here. You can do me a favor. You take your boys and go on, and that other bunch too...

Johnny, with a long-standing hatred for cops (after he "made a deal with a cop once") refuses to deal: "I said I don't make no deal with no cop."

When things start breaking up, Johnny has a few words with his old girlfriend - a tight-sweatered Britches (Yvonne Doughty), now a member of Chino's gang. A man of few words, Johnny has little to say to her:

Britches: Oh you remember, the last weekend we went out scrambling. Before the club split up.
Johnny: Oh, yeah.
Britches: How have ya been?
Johnny: Well, I'm still swingin'.
Britches: I didn't know what happened to ya. Well, it's been a year I didn't see you. I thought about you.
Johnny: Listen, I'll see you later, OK?

Now that his gang will remain in town, Johnny goes back inside the Cafe to retrieve his "gold" trophy from Kathie. He tells her that her father ought to have arrested the driver, because he was also at fault. Kathie defends her father's behavior but then accuses both Johnny and her father of being fakes:

Kathie: He was afraid of making a mistake. He was afraid of losing his job. He's the town joke and I'm stuck with him. He doesn't got any business being a cop. No more than you have with that [fake trophy]. He's a fake - like you. Well, you've impressed everybody now, big motorcycle racer. Why don't you take that back so they can give it to somebody who really won it?
Johnny (irritated): Say what? Who are you? Some girl who makes sandwiches or somethin'? Your father wears that hat that says he's a big important man and you start tellin' me what to do. Nobody tells me what to do. You keep needlin' me, and if I want to, I'm gonna take this joint apart. And you're not gonna know what hit ya.

Johnny saunters into the bar and orders a beer. A gang member asks: "Hey, Johnny, what's the pitch, are we leavin'?" Johnny replies: "Not just yet." The foam on his beer bottle overflows, symbolic of burgeoning feelings of conflict within Johnny's psyche.

When night comes, further tension mounts as Chino's gang hovers outside the Police Department's jail, and Johnny's cyclists carouse and drink heavily within Bleeker's Cafe. Both gangs threaten to take over the operations of the town, and even members of Johnny's gang suggest 'springing' Chino from jail because of the "phony cop." Chino's gang members terrorize the town's operator and cut off telephone line connections at the main switchboard. Meanwhile, Johnny's gang - to administer proper justice - rides to the house of Charlie Thomas, apprehends him and drags him to the police department jail to share the cell with the drunken Chino.

Afterwards, while a lot of partying and drinking is going on in the bar, Johnny runs into his old girlfriend Britches outside - she begs to talk to him again ("Talk to me, Johnny. Sing me a song. Buy me a beer...I wanna know how you've been, Johnny...You gotta date?"). She is still pining for him and his attention, remembering when she first joined his gang and fell in love with him - but was quickly abandoned:

Britches: We really got ourselves hung on the Christmas tree, didn't we? Boy, was I green. Was I really green! I thought I was really livin' it up. I had me a guy and we were really gonna go. But we had a lot of yuks, anyway, didn't we, Johnny? Well say it, can't ya say something? Please, Johnny, I won't get on your back. I wouldn't do that. But we had a lot of yaks, anyway, didn't we?
Johnny: (coldly) What do you want me to do, send you some flowers?

Inside the bar, the overwhelmed and helpless owner Frank is worried that the gang has turned destructive and is wrecking his place - and seeks out Johnny to beg him to muster his authority to subdue his followers, but Johnny ignores him. Some of the townsfolk take the law into their own hands and release Charlie from the jail. They arm themselves for protection and to bring the town's chaos to a halt: "You wanna wait until somebody gets killed before we take action?" One dissenter Bill Hannegan (John Brown) protests: "Two wrongs never made anything right. When you start using guns...!" After they leave, Chino notices the jail cell door left open, and also escapes.

Meanwhile, Johnny's gang has entered Mildred's Beauty Salon and destroyed much of its insides. Johnny is out looking for Kathie, who has left the cafe to go warn her father about the dead phone lines. The bikers spot Kathie ("Johnny's girl") walking by the vandalized hairdresser's salon and begin to terrorize her. They chase her on their bikes and then noisily circle around her, until Johnny, in a memorable scene, comes by and heroically rescues her from danger by telling her to "get on" behind him on his huge bike. Then he roars out of town with her behind him on his shiny, phallic motorcycle. Under the spell of the moonlight to the accompaniment of jazzy music, they ride together - her hands around his waist, hair blowing wildly.

He takes her to safety in a little park in a forested glade. After dismounting, he forcibly grabs and brutishly kisses and hugs her. Almost passive or dazed, she hesitantly replies that she cannot respond passionately:

Kathie: I'm sorry. I-I can't fight back. I'm too tired. It would be better, wouldn't it? Then you could hit me.
Johnny (berating her attitude toward him): You think you're too good for me. Nobody's too good for me. Anybody thinks they're too good for me, I make sure I knock 'em over sometime. Right now, I can slap you around to show you how good you are. And tomorrow, I'm someplace else and I don't even know you or nothing.
Kathie: Do you want to?
Johnny: I wouldn't waste my time with a square like you. What do I want to knock myself out for? I'm gonna take you back and dump you. Come on, where're you going?
Kathie (desiring him, she softly replies): Johnny. (She gently touches his arm.)
Johnny: Quit that.
Kathie: It's crazy, isn't it? You're afraid of me. I don't know why, but I'm not afraid of you now. You're afraid of me.
Johnny (disbelieving): I'm afraid of you? Are you cracked? Come on, get on.
Kathie (walking closer toward him): I wanted to touch you. I wanted to try anyway.
Johnny: Try what?
Kathie: I don't know. I wanted to make it the way I always thought it would be sometime - with somebody. The way I always thought it might be. You're still fighting, aren't you? You're always fighting. Why do you hate everybody?

Oddly attracted to him, Kathie continues to ramble, describing how she has never ridden on a motorcycle before [a metaphor for her virginal sexual experience]. She tells him that it was a very satisfying experience - she nuzzles next to his machine and rubs it:

I've never ridden on a motorcycle before. It's fast, it scared me, but I forgot everything. It felt good. Is that what you do?

She is envious of him - she has often dreamed about leaving her depressing, routine, small-town lifestyle by taking off with someone she would meet and have coffee with in the cafe.

Kathie: You know what I used to think about? I used to think about it alot after my mother died - that somebody would come here and stop at Uncle Frank's place, and buy a cup of coffee or something, and he'd like me right away and take me with him. Johnny, you were going to give me that statue. Will you give it to me now?
Johnny: Why?
Kathie: I don't know. I just wondered if you still wanted to give it to me, that's all. It's crazy.
Johnny: Where did you want this guy to take you - this guy who had a cup of coffee?
Kathie: I don't know. Wherever he was going, I guess. I'm shaky. I wish I was going someplace. I wish you were going someplace. We could go together.

When Johnny doesn't respond to her romantic fantasy and rejects her crazy dream, she begins crying and hugs him ("Johnny, Johnny, I love you"), but he pushes her away. Then embarrassed, she runs away. One of the townsfolk Art Kleiner witnesses the incident and misunderstands, assuming that Johnny is intending to rape her. Moments later, Johnny catches up to her on his bike , when she slaps him. He is now intrigued, attracted and aroused by her freshness and innocence. She breaks free and flees again, crying.

Kathie witnesses Johnny attacked on his bicycle by a vigilante mob of townspeople. She runs to her father's office to beg him to stop the violence and rescue Johnny ("Aren't you gonna do anything?"). Her distraught father has been drinking straight 90 proof whiskey alone at his desk with a pistol lying in front of him - he is hesitant to help, vowing: "What can I do?" She accuses him of complacency to shame him into action:

Kathie: They've got Johnny. You've got to help him. They're going to beat him up or something.
Bleeker: I tried to talk to him.
Kathie: Don't you even care?
Bleeker: What can I do?
Kathie: Nothing, I guess. But if you don't do something, you're worse than any of them.
Bleeker: They brought it on themselves. I saw it coming, but what could I do? Charlie Thomas is a bully. He was a bully in the Third Grade. (He picks up the pistol) What am I supposed to do? Shoot somebody?

Meanwhile, Johnny is dragged into a building where he is pinned down while being viciously beaten up - the townspeople are far more violent than anything the gangs had done. During the beating, Johnny defies his attackers: "My old man used to hit harder than that." Kathie and her father arrive where the beating is taking place (Hannegan and Thomas' Hardware), but the mob doesn't want the "soft-hearted" police chief to interfere. They explain that they are teaching the hoodlum a lesson their own way - they are punishing him for representing unorthodox freedom:

Charlie: We've got a little job that's got to be done.
Bleeker: This is my job.
Art Kleiner: You won't have it long.
Another: We're doing something that should have been taken care of before this - pounding a little respect for law and authority into this guy's thick skull.
Bleeker: That's not the way to do it.
Charlie: You got a better way? You've had a lot of time to try it.
Another: Harry, look, you're too soft-hearted. This is no time for kindness.
Bleeker: It's as good a time as any.
Charlie: We're doing this our way. We're gonna make good and sure he doesn't try anything like this soon again.

Bleeker stands up to the mob, explaining: "Now I don't know what he's tried or what he hasn't tried. This boy is in my custody. If he's done anything to deserve punishment, he'll get it - but in the right way and not from you."

Johnny breaks away from his captors, races away to escape through dark streets, and finally staggers back to his downed cycle. He gasps and sobs as he looks up into the dark skies. As Johnny attempts to leave town on his bike, he receives another angry response from a larger mob of citizens who have set a trap on main street. Someone tosses a tire iron at his moving bike's wheel spokes, causing him to be thrown free of his bike, and sending the bike plunging out of control. The cycle inadvertently strikes and kills an elderly bystander in the crowd - Jimmy. The angry townspeople now become a lynch mob, but are held in control by the arrival of county Sheriff Singer and an entourage of police cars. Johnny is detained while order is restored to the town ("Round up everybody on a motorcycle"), but the biker faces possible manslaughter charges. Johnny isn't allowed to pick up the trophy, now cast onto the ground.

At the subsequent hearing, witnesses testify before Sheriff Singer. Johnny protests his innocence of the charges: "I didn't kill nobody. There were some of those guys just comin' up the street after me and I just took off, that's all. Maybe something hit my cycle or something like that, I don't know what happened." Kathie is allowed to defend Johnny, explaining that it wasn't Johnny's fault. After Sheriff Singer asks if she has any proof, and then senses something between them, he mentions a possible attraction between them: "You haven't fallen for this fella, have you?" Kathie looks up and says: "No, no I couldn't." She realizes that any relationship would be impossible.

When her Uncle Frank accuses Johnny of attacking her in the park, Kathie vigorously defends Johnny:

No, no, no, listen, Uncle Frank's all wrong. He helped me. They went after me on motorcycles...I wasn't trying to get away from him. I was trying to get away...

Frank also testifies that he saw someone throw a tire iron at Johnny's bike, and that Johnny is innocent of the charges.

Before Johnny is let "off the hook," Sheriff Singer lectures a silent and sullen Johnny - the film's stinging, moralizing condemnation of the biker and all others like him:

I don't get you. I don't get your act at all, and I don't think you do either. I don't think you know what you're trying to do or how to go about it. I think you're stupid, real stupid, and real lucky. Last night, you scraped by, just barely. But a man's dead on account of something you let get started, even though you didn't start it. I don't know if there's any good in you. I don't know if there's anything in you. But I'm gonna take a big fat chance and let you go. There'll be a hearing on this tire iron business. You'll get a summons and you'd better show up.

Johnny is ordered to be set free and is given his trophy back by the kindly, patient official. The Sheriff prompts him to say 'thank you':

Don't you want to say anything to these people? What's the matter? You been hit over the head so often you don't know when you're getting a break? You could at least say 'thank you.'

Though grateful for the unexpected kindnesses from Kathie and the others, he is unrepentant and unable to express his thanks. He cannot say "thank you." Kathie explains for him: "It's all right. He doesn't know how."

Johnny is freed by the Sheriff but on the condition that his entire gang of bikers never enter the town again:

Every one of you monkeys is down in my book, and every stick of damage around here will be paid for. You've got ten minutes to clear out. Just stick your nose back in this county, any of ya, and you'll never see daylight again as long as you live. Now git.

On his way out of town, Johnny stops one last time at Bleeker's Cafe for coffee in the film's final scene. He has come to say goodbye to Kathie - she is sitting at the far end of the counter drinking coffee with her father. After her father leaves briefly to speak to two other officers, Johnny wipes his mouth and eyebrows, and sits resting his head on his fist. Painfully unable to find the right words to speak, he rises. At the door, he pauses and dangles the motorcycle trophy from his hand, and then - after much indecision - walks back in and places it on his end of the counter. He pushes it toward her and vaguely smiles - the first time in the film. She accepts his gesture and memento with a return smile of her own, acknowledging his emotional breakthrough. He has relinquished his stolen, beloved trophy and offered it as an insignia to the understanding girl who has redeemed him. And then he is quickly gone, leaving the deserted town on his bike.