"Please," she begged. Karina didn''t know what she begged for, maybe for the flare to do its work or, maybe, for the pain to stop. She never saw which way the flare headed. A coughing fit that ended with a strong taste of blood in her mouth delivered her back into the comforting realm of darkness, back to where problems ceased to exit, and back to where pain could not find her.

Fifteen-year-old Karina expects hardships and surprises during her five-month school term at sea aboard the Star Fin, a research vessel designed to turn troubled adolescents into responsible adults. Classes in marine biology and advanced scuba diving help her gain confidence and self-control; but nothing prepares her for encounters with moray eels, a dangerous Portuguese man-of-war, deadly sea snakes, and man-eating sharks. When blood-frenzied sharks viciously attack a family of capsized kayakers, Karina''s skills and courage are put to the ultimate test.

Her skills are tested even further when Karina and her peers attempt to explore a shipwreck deep in the ocean. After the group is sabotaged and stranded by a fellow classmate, everything that can go wrong, does. Are Karina and her friends strong enough to survive the elements, a sinking ship, and decompression sickness?