Twelve-year-old Jasmine Lopez loves exploring the coral reefs around Fiji where her marine biologist parents are stationed, and though young, she is already a certified scuba diver, a fact that her ten-year-old brother Arjun seems to resent; in fact he seems to believe he already knows everything about diving, and certainly does not want help from his older sister--until his overconfidence and defiance leads them both into a confrontation with a reef shark.