I think this is Roshani Chokshi's first adult story and it's really quite good! I would call this a fairy-tale inspired story, or maybe a re-mix, since it's not a true re-telling of any one fairy tale or a mashup of two or more.
I really loved the ideas behind the story and the events that unfold. Not only do Ambrose and Imelda need to learn love is not always lost for good, but there are other lessons about love they need to learn. I really enjoyed the adventures they had. I only wish there'd been some sexy times, but that's a personal preference and the story doesn't really need them to feel complete.
Hats off to Roshani Cholshi for trying and writing something new. I'm really impressed with Once More Upon a Time and look forward to hopefully reading more adult books by her.