Underwater investigator Hannah Sampson and her partner are suiting up for underwater training in the British Virgin Islands when a plane nosedives into the water and disappears.They save eight people-and lose four. Hannah plunges into an investigation to see if one of the passengers was a target and who would be desperate enough to kill all those people.And as she copes with a nine-year-old survivor, a shady suspect, a shaky relationship-and an approaching hurricane-Hannah begins to feel she might have gotten in too deep.