Lies Beneath, the predecessor to Deep Betrayal, was one of my more favorite mer-books from recent years. It was one of the few narrated from a male perspective, it was a darker imagining of mermaids than what most us were used to, and it had excellent characters and romance. Deep Betrayal was just as good if not better.
Oh yeah, spoilers. Don't read this if you haven't read Deep Betrayal.
I really liked the direction Anne took with Lily's dad. The book begins with Calder and Lily revealing that he is in fact a merman, which is the catalyst for most of the events in the book. It was interesting to see where that took his psyche and the effects it had on his family.
And to further that, the inevitable build up towards Lily's transformation was incredibly suspenseful and perfectly done. I couldn't stop reading.
Lily's narration is also awesome. It's different from Calder's, but ties in very well. It's like peanut butter and jelly. Props to Anne on that one. I loved all the Tennyson in here as well, it all tied in so great with the story and the tone.
A lot of romances don't seem to click with me, but Calder and Lily are excellent together and you can really feel that when reading the book. It doesn't feel forced, cheesy, or unnecessary at all.
You definitely need to read Lies Beneath first, just to understand what's up, but this book definitely has it's own merits. It's different enough from the first to keep it interesting, but consistent enough from the tone of the first novel.
Easily one of the best mermaid oriented books on the market right now. The characters and places were all I could think about for days afterwards. Read this book.