Serafina, Neela, Ling, Ava, Becca, and Astrid, six mermaids from realms scattered throughout the seas and freshwaters, were summoned by the leader of the river witches to learn an incredible truth: the mermaids are direct descendants of the Six Who Ruled—powerful mages who once governed the lost empire of Atlantis. The ancient evil that destroyed Atlantis is stirring again, and only the mermaids can defeat it. To do so, they need to find magical talismans that belonged to the Six. Serafina believes her talisman was buried with an old shipwreck. While researching its location, she is almost discovered by a death rider patrol led by someone familiar. . . . The pain of seeing him turned traitor is devastating. Neela travels to Matali to warn her parents of the grave threat facing their world. But they find her story outlandish; a sign that she needs to be confined to her chamber for rest and recovery. She escapes and travels to Kandina, where her talisman is in the possession of fearsome razormouth dragons. As they hunt for their talismans, both Serafina and Neela find reserves of courage and cunning they didn't know they possessed. They face down danger and death, only to endure a game-changing betrayal, as shocking as a rogue wave.

Serafina, Neela, Ling, Ava, Becca, and Astrid, six mermaids from realms scattered throughout the seas and freshwaters, were summoned by the leader of the river witches to learn an incredible truth: the mermaids are direct descendants of the Six Who R

Serafina, Neela and four others have successfully escaped Captain Traho and his men after their hideout with the river witches was stormed. They must stop an ancient evil from escaping its icy prison by finding six talismans hidden by Serafina's ancestor hundreds of years before. With all the Mer nations looking for them and no clue where to start, will the mermaids find the talismans before the monster is released?

Deep in the ocean, in a world not so different from our own, live the merpeople. Their communities are spread throughout the oceans, seas, and freshwaters all over the globe. When Serafina, a mermaid of the Mediterranean Sea, awakens on the morning of her betrothal, her biggest worry should be winning the love of handsome Prince Mahdi. And yet Sera finds herself haunted by strange dreams that foretell the return of an ancient evil. Her dark premonitions are confirmed when an assassin's arrow poisons Sera's mother. Now, Serafina must embark on a quest to find the assassin's master and prevent a war between the Mer nations. Led only by her shadowy dreams, Sera searches for five other mermaid heroines who are scattered across the six seas. Together, they will form an unbreakable bond of sisterhood and uncover a conspiracy that threatens their world's very existence.

Deep in the ocean, in a world not so different from our own, live the merpeople. Their communities are spread throughout the oceans, seas, and freshwaters all over the globe. When Serafina, a mermaid of the Mediterranean Sea, awakens on the morning of her betrothal, her biggest worry should be winning the love of handsome Prince Mahdi. And yet Sera finds herself haunted by strange dreams that foretell the return of an ancient evil. Her dark premonitions are confirmed when an assassin's arrow poisons Sera's mother. Now, Serafina must embark on a quest to find the assassin's master and prevent a war between the Mer nations. Led only by her shadowy dreams, Sera searches for five other mermaid heroines who are scattered across the six seas. Together, they will form an unbreakable bond of sisterhood and uncover a conspiracy that threatens their world's very existence.

Once a lost and confused princess, Serafina is now a confident leader of the Black Fin Resistance (BFR). While she works on sabotaging her enemy and enlisting allies for battle, her friends face challenges of their own. Ling is in the hold of Rafe Mfeme's giant trawler, on her way to a prison camp. Becca meets up with Astrid and learns why the Ondalinian mermaid is always so angry: she is hiding a shameful secret. Ava can't return home, because death riders await her arrival. And it is getting more and more difficult for Mahdi, Serafina's betrothed, to keep up the ruse that he is in love with Lucia Volerno. If Lucia's parents become suspicious, his life--and all of Sera's hopes--will be extinguished. Political intrigue, dangerous liaisons, and spine-tingling suspense swirl like a maelstrom in this penultimate book in the WaterFire saga. Praise for Deep Blue "A richly imagined novel. Themes of conquering fear and believing in oneself are woven throughout, along with an acknowledgment of humans' environmental impact on the sea and its inhabitants. Despite the high stakes and a few frightening moments, the story is never over serious; it's just right for readers who have grown up with, but aged out of, The Little Mermaid and the Disney Fairies franchise." - Publishers Weekly "A fantastic addition to the genre of mermaids, this book will also appeal to readers of action and those who appreciate usurped leaders taking back their kingdom. It starts with a common enough concept: a royal girl who is worried about her betrothal and about love. Donnelly then adds layers of complexity to the tale and weaves her story into that of Atlantis. Friendship, trust, and responsibility are major themes as Sera struggles to grasp that she is really her kingdom's only hope. Quick-witted, loveable characters and a well-planned fantasy world make this an all-encompassing book. Readers will eagerly await future volumes and the answers they will provide." - VOYA "Best-selling Donnelly (Revolution, 2010) builds an alluring mermaid civilization and history, filled with painterly descriptions of Sera's underwater palace and its unearthly architecture, her sumptuous wardrobe, and the menagerie of half-human, half-marine animal denizens. There's also plenty of romantic tension with handsome mermen, strife between merls (that's girl mermaids) from rival regions, and some powerful female friendships amid the fast-paced plot, filled with wondrous magic." - Booklist

Once a lost and confused princess, Serafina is now a confident leader of the Black Fin Resistance (BFR). While she works on sabotaging her enemy and enlisting allies for battle, her friends face challenges of their own. Ling is in the hold of Rafe Mfeme's giant trawler, on her way to a prison camp. Becca meets up with Astrid and learns why the Ondalinian mermaid is always so angry: she is hiding a shameful secret. Ava can't return home, because death riders await her arrival. And it is getting more and more difficult for Mahdi, Serafina's betrothed, to keep up the ruse that he is in love with Lucia Volerno. If Lucia's parents become suspicious, his life--and all of Sera's hopes--will be extinguished. Political intrigue, dangerous liaisons, and spine-tingling suspense swirl like a maelstrom in this penultimate book in the WaterFire saga.