Sweet and with simple poignancy, Cinder is a poor child wrecked by a terrible incident that killed her family and destroyed some of her limbs, leaving her with mechanical appendages which caused immediate scorn and prejudice. A short story when Cinder first arrived with her new father to Beijing. Her jumbled memories from her past, her new ability as a cyborg, her relationship with her new sister, Peony, and her stepmother, Adri. Basically a shortened version of 'Cinder' but most appropriately Cinderella-themed than the book. 
 I don't think its a necessity to read the prequel before reading Cinder. Even without it, you can enjoy Cinder as it is. There are many hints in the story which was related to the rest of the series and can be a let down if you're seeking new things. A good introduction for the novels if you're recommending it to someone.