When sixteen-year-old Cate Carlisle is made an offer she can't refuse, she drops everything to help her friends at an Australian marine sanctuary.

But there is trouble in paradise. A boy has mysteriously disappeared. Shadowy figures and strange lights haunt the ocean, and hyper-aggressive sharks are wreaking havoc.

Cate needs her natural spy instincts, plus the help of her geek brother and glamorous friends, to save the animals and humans from an eco catastrophe.