"Youth Aflame" is an exploitation film that was intended to both fill theater seats with all sorts of talk of debauchery as well as warn against the behaviors it glamorizes! I love these sorts of film...and recommend you try it if you can tolerate these sorts of things!
Katy is a lame girl for many reasons. First, although her sister Laura is wild and headed for a major fall, Katy repeatedly covers for her in some misguided attempt to help her. Second, well, she's just really lame....and loves to hang down at the 'milk bar' with the other teens...where they dance, socialize and drink milk! As for Laura, she's infatuated with a criminal who pretends to want to marry her. And, since Laura is apparently no smarter than a peanut, she helps the guy but stealing her father's gun and giving it to the boyfriend! You can clearly see it's all headed for disaster....and DEATH!!!!
This film is unintentionally funny....like most exploitation films. While it's not as over the top as the best (worst???) of them (such as "Sex Madness"), it is needless to say quite entertaining because it's so bad and the message delivered so poorly....with bad acting, dialog and a silly message about crime not paying. Worth seeing if you like this sort of thing..otherwise, it is clearly a very bad film.