Mother Goose (Hal Smith) is arrested for disturbing the peace with her naughty stories; at her trial, she recounts several of her saucy tales to the judge, causing the occupants of the courtroom to become more and more sexually stimulated until, at last, they can contain their excitement no longer.
The success of Ralph Bakshi's Fritz the Cat (1972), the first animated film to receive an X-rating from the MPAA, kick-started a craze for animation full of adult humour and sex. Once Upon a Girl, which begins as live action but turns to animation to depict the amorous adventures of several fairy-tale characters, is about as risqué as it gets: Jack (he of the beanstalk) is depicted as a young pervert with a huge member, who shags a tree, goes at it with a gypsy woman, ejaculates on some magic beans, and clings on to the end of a giant's penis after hiding in the vagina of the big fella's wife; Prince Charming doesn't slip a glass slipper onto Cinderella's foot—he slips himself into Cinderella instead; and Little Red Riding Hood is repeatedly boned by randy woodsmen on her way to a wedding (which eventually turns into an orgy).
As undeniably vulgar as all of this is, the film proves to be crude in more ways than one, with a crap script full of dreadfully unfunny jokes, cheap-looking animation, and lousy voice talent. Quickly becoming both repetitive and boring, Once upon a Girl is a waste of animator's ink and paint, and the viewer's time.