Marine biologist Corrie Duval saw something as a child, something she could never forget. To her colleagues at the university, she is a research scientist collecting ocean data. But Corrie’s experience as a young girl led her to a secret online life consumed with finding evidence of mythical sea creatures. Forgiveness is something Zeballos Artino can’t grant his recently deceased father. George Artino withheld crucial information about Zeb’s heritage, information that may explain Zeb’s extraordinary abilities. Now, Zeb must search for answers while concealing his hidden talents. Together, they navigate dangerous waters, dodge ruthless fishermen, and dive into uncharted knowledge. They may find the answers they desire, but what other questions will emerge from the depths of the ocean?

Marine biologist Corrie Duval has so many questions about the strange fish she found. Unfortunately, her results aren’t giving her clear answers, and her professor is growing suspicious about her late-night analyses and secretive manner. Zeballos Artino still searches for his own answers, but he’s not the only one. Someone is following his boat, and if Zeb won’t tell them what he knows about the strange fish and its bizarre effects, they will make him talk. Corrie and Zeb fall deeper into a world of cut-throat henchmen and scheming tycoons who are on the hunt for the same thing they are—mysterious creatures in the sea.

The more marine biologist Corrie Duval learns about the mysteries of the open ocean and the illusive creatures that inhabit it, the more questions she has. Where are these creatures coming from, how are they related, and just what is Zeballos Artino hiding? Zeb wishes he could answer Corrie’s questions, but there is so much he can’t say, and even more that he doesn’t know himself. The shadowy figure of the woman in the water plagues him with riddles he can’t decipher, and his late father’s notebook provides only frustrating clues. But when Zeb discovers someone else is attracting these mysterious creatures with the same sonar device installed on his own boat, he and Corrie must race to uncover the truth before this secret world is exposed and exploited.

Time is running out, but legends are elusive. Marine biologist Corrie Duval is haunted by the murders she witnessed. She buries herself in work to forget. It's not so easy when her friend Zeballos Artino is desperately sick. Without a cure, he can only hope his mother's people have answers. But the pale folk are proving impossible to find. When Corrie and Zeb meet with a researcher keen on studying Zeb's mysteries, answers are on the horizon. But the notebook of Zeb's father hints at a greater peril than Zeb's sickness. Stormy seas hide secrets in their depths, and Corrie and Zeb don’t know if wonders or terrors wait at the end of their search. They must find answers before the ocean swallows their boat—and them—without a trace.

Not all monsters have scales. Spunky marine biology student Corrie is an unlikely champion of legendary sea monsters, from friendly unicorn fish to the giant grumpy Kraken. Corrie's ailing friend Zeb is one of those legends. When they discover Zeb’s true heritage, his secretive people threaten Corrie for prying into their world. Corrie feverishly searches for a cure for Zeb’s illness, but watchful eyes are everywhere. Zeb’s new friends—the few on his side—won’t help against enigmatic hunters hellbent on silencing Corrie. Their frightening powers have no limit, and Corrie’s very mind is at stake. If she can’t solve this scientific mystery, and if Zeb can’t protect her, their future is blacker than the ocean’s abyss.