The coastal town of Bristol Cove is known for its legend of once being home to mermaids. When the arrival of a mysterious girl proves this folklore all too true, the battle between man and sea takes a very vicious turn as these predatory beings return to reclaim their right to the ocean.

Jane Tennant, the first female Special Agent in Charge of NCIS Pearl Harbor, and her unwavering team of specialists balance duty to family and country while investigating high-stakes crimes involving military personnel, national security and the mysteries of the sun-drenched island paradise itself.