Pirates are the most despised human beings around, they're filthy, crude, and they rob from the richest of the rich. Charlie is apart of the most powerful crew in all the seven seas, The Black Diamonds. Her brother, Nate, is the captain but only by tragedy. Their crew are bounded together with a bond stronger than blood, death. Something inhuman murdered their first captain, Black Blood, who was a ruthless but caring man at the same time. The only father figure of Charlie and Nate, who were orphans before he took them in his care, was killed right before their eyes. The Black Diamond crew hunt for these inhuman beings called mermaids. Their voices are deadly beautiful and their songs are laced with magic to lure humans in so they can kill them. The mermaids are the common enemy of all people, pirates and people of society alike. When the ship is attacked one night, Charlie is pulled into a whole new world under the sea. She's taken captive and discovers the mermaids might not be so evil after all... Which life will she choose for her, the pirate life or a life engulfed in water?