Katy White, is at death's door in an emergency hospital but is hanging on long enough to tell her story. In flashback, Katy tells of her widowed father , a bank guard trying to raise two teen-age daughters...Katy the nice girl and her sister, Laura the not-quite-nice girl. Katy tries to guide her sister away from bad company, but isn't having much success. Al, Laura's hoodlum boyfriend, asks her to steal her father's gun.She does so. Meanwhile, under the guidance of Helen Clark, a kindly policewoman, the better-supervised kids open up a JIVE Club in order to keep off of the Mean Streets and not drift into juvenile delinquency. Joy and Laura join the club but Laura only in order to keep late hours with Al. But Joy is keeping a watchful eye on Laura.