An adult fable told with childlike simplicity, “Year of the Fish” updates an ancient Chinese version of the “Cinderella” story with imagination, charm and just the right amount of sweetness.

Our put-upon heroine is Ye Xian (An Nguyen), a mousy naïf whose new job at a sleazy massage parlor promises happy endings — for the clients, at least. When she balks at fulfilling her job description, Ye Xian is demoted to cleaning toilets and cooking meals for the parlor’s wicked madam, (Tsai Chin), and grasping employees. Little does she know that an enchanted fish, a witchy soothsayer and a handsome musician are about to save her from her servitude.

Filmed in New York’s Chinatown using a digital variation on the animation technique known as rotoscoping, “Year of the Fish” straddles the wavering line between reality and its simulation with pleasing calm. Instead of the pulsing images of the Richard Linklater films “A Scanner Darkly” and “Waking Life,” you have a more subdued, mellow style that’s easier on the eyes and the equilibrium. And the movie’s smudged skylines and pearly-pastel streets do much to soften the story’s sweatshop-and-slavery grittiness.

Written and directed by David Kaplan, “Year of the Fish” packs more sadness than the familiar fairy tale but offers its own fantastical delights. Ye Xian’s party dress, made of teardrops, suits her — and her story — perfectly.