Definitely not your ordinary mermaids…Deep Betrayal is the sequel to Lies Beneath and takes place about a month after the events of that book. Lily has been sent away from her family’s home on the shores of Lake Superior in order to keep her safe. All she can think of is Calder, her merman boyfriend. Lily also feels strangely attracted to the water.Like the first book, this is a darker, more sinister take on mermaids. The author blends intriguing mermaid lore with native Indian legends to create a captivating read. Even Coyote makes an appearance. The narrative is enhanced by the addition of mermaid themed poetry. The underwater sequences are beautifully detailed as well.I enjoyed Deep Betrayal more than Lies Beneath. I think it’s because the characters had another level of development. Whereas in the first book Calder was a little creepy, in this book he became the family’s protector and mentor. Calder even took his relationship with Lily a step further, attempting to take her on dates like a regular boyfriend. Calder seemed a little more human in this book. In Deep Betrayal, Lily’s father Jason realizes his calling and begins to spend more time in the lake, abandoning his family. Calder takes him under his wing (fins?) and is showing Jason how to live as a merman. Meanwhile, something sinister is going on in the town and the surrounding areas. Someone or something is killing off the local townspeople. Calder and Lily work together to find out who or what is responsible.This is a fun book to read if you ignore a few of the little inconsistencies and just enjoy the ride. (I’m not too sure that a human could deep dive 20 fathoms without a sub or specialized equipment). Also, Lily holds her breath for quite a while. I’m sure it’s possible, but a tad unrealistic.Despite these niggling little things, Deep Betrayal still was an enjoyable read. For a darker take on mermaids, Deep Betrayal fits the bill (fins?). I’m looking forward to reading more books by this author.Thank you to NetGalley and Random House for a review copy of this book. Review posted on Badass Book Reviews.