Six teen mermaids are tasked with saving the seas from an ancient monster known as Abbadon. But the legend that comes to them in a dream is one they all believed was just a story.
Serafina's betrothal ceremony will not only cement her kingdom's ties with nearby Matali, but it will also solidify her position as heir to the throne in Miromara. But the ceremony comes to an abrupt and tragic end when the kingdom is taken and the reigning Regina, Serafina's mother, is shot. Sera and her friend Neela have no choice but to take to the seas and seek safety. It is at this point that they both realize the Iele are real. The soldier on their tails knows of their dreams and has orders to find all six of the mermaids before they make it to the sea witches' cave. If they're caught, it will not only mean the end of Miromara but it could mean the destruction of the whole undersea realm if not the world beyond.
This first in Donnelly's Waterfire Saga was a bit underwhelming. It is a teen release but I still expected it to be a bit more serious and mature than it turned out to be.
The world building is definitely a strong point in the book. I did love the ocean realms and the fact that the whole story is steeped in this world. The language and history, the food, even the slang terms the characters use are completely unique to Donnelly's creation.
The characters, though, were an issue for me as an adult reader. I think they're fine for a younger audience - they're certainly likable as heroines and it's easy to sympathize with their plight. They simply come across a bit silly even after the action begins.
I had higher expectations, obviously. If I were still a bookseller, though, I honestly would have no issue recommending this to a thirteen-year-old, depending on their reading preferences of course. I guess I feel a little guilty giving this one too much of a bad review considering my only real issue is that it didn't satisfy me - as a thirty+ year-old reader, which I think is unfair considering it's a teen release. So for me Deep Blue was meh, and I'm guessing most adult readers will agree. For a younger teen audience it might be perfectly delightful.