Cinderella.

Zezolla and her family live mid 20th century, where fashion is practically everything. As her father is won over by a selfish woman named Claudette, Cinderella must keep her new step-mother from murdering the only family she has left. Add in an anti-social mermaid literally living in a cave, a bored prince with an ear for rock n' roll, and the glamour of the 1950's and one'll find that this story can't grow old.