Anthropology professors, Laly Lawrence and Sarah (Sugar) Stevens are working in the Bahamas when their dive group sees an unusual and unreported storm heading straight toward them. Sugar dives down to get Laly to safety but the storm catches them in its mighty grip and pummels them beneath the ocean waves. When they are able to surface they seem to be between English and Spanish ships in the midst of a bloody battle. Shock and horror take hold as they see men fall to their deaths before their eyes. Pulled from the sea by the English sailors, they soon discover they've somehow been transported back in time to the year 1678 where they are believed to be the mythical sea creatures: mermaids. They have to find a way back to their own time but a blood-thirsty pirate and other evil characters stand in their way. Also, the dashing English Captain, Devon Bradley puts another even more dangerous obstacle in their path...love.