An erotic tale of a bright, young and Musically-gifted African-American woman who grows up in the 1970s, jaded by her abusive childhood. During her attempt at rock and roll stardom, she is distracted by a tragic discovery: she may have become her violent father.

I believe its way over 30 words. Not sure thats a rigid rule, but it certainly makes it easier to grasp. Some of the information might not be necessary for the logline.

I know, this suck, but you get the point...:
Jaded by an abusive childhood, a musically-gifted African-American woman struggles, trough the 70's world of sex and rock-and-roll, against becoming her violent father.