The Deep, by Helen Dunmore

Sapphire may look like a normal teen girl, but there's nothing ordinary about her. She possesses an incredible secret: She is part mer (yes, as in mermaid), and this heritage allows her to exist as easily under the sea as she does on land.

Having just helped prevent a tidal wave from destroying her (human) town, Sapphy and her brother, Connor, are called upon once again. And this time both worlds, land and sea, are being threatened. A powerful monster called the Kracken has awakened from a centuries-long slumber, and he is hungry. If he is not lulled back to sleep, his existance would end life for everyone everywhere. And Sapphy, with her mixed blood, is the only one who can enter The Deep and stop him. 

But the battle with the Kracken is small compared to the inner struggle going in within Sapphire's mind and heart. The pressure of living in two worlds, yet striving to keep them separate (and secret), is becoming increasingly difficult for her. She knows she must choose one or the other soon or go mad. But how to decide?

The Deep is the third book in Helen Dunmore's Ingo trilogy. Here readers see lots more of familiar characters, get to know others better, and meet new ones (both good and evil). And, as do the characters, we also get to go deeper into the world of Ingo and are privy to more of its carefully-guarded secrets. All in all, The Deep is a fantastic book and an excellent continuation of an amazing series. --AJB

Ingo, book 1

Ingo, book 2

p.s. Reader take note: If you're looking for a happy, fluffy mermaid story where sea creatures dance and sing and gaze longingly at the human world, turn to Disney. You will not find that sort of thing with the Ingo books, which are heavy on the mythology. 

p.s.s. Ingo is also a great fantasy choice for readers who want stories with little to no romance. That is: This is NOT a kissing book.