I normally don't buy romance fiction, but I've always been interested in Greek Mythology. There was some physical romance in this book, but I wouldn't call it erotica. The author added some details to some popular Greek myths and created an engaging story. We get to know Pandora, Prometheus, and Epimetheus much better. There are some flashbacks to interactions with Zeus, Hera, and Hecate.
I can't say I know how much mythology the author invented for this book and how much she used from existing texts. It was an interesting read regardless.
The character dialog and narration was primarily written using modern English and few modern colloquialisms. It may sound out-of-place to some people. I didn't mind it once I got used to it. I sometimes do the same when trying to write ancient historical fiction.
Grammatically I had no problems. Though i do like more of a mix between short and long sentences, it ultimately wasn't a problem for me. Good grammar and well-written, easy to follow along and it kept me curious enough to keep reading. Most of the time I spent reading Pandora's mistake, I had trouble putting it away for later.