Olivia is your average teenage mermaid. She runs away to be with the Siren Sisters the day before her seventeenth birthday so she doesn't have to marry the merman her father set her to marry when she was born. The Siren Sisters tell Olivia she can become an outcast with them if she can prove she's worthy enough by luring a human into the ocean. Little does she know she doesn't have the heart to kill a human. The Siren Sisters turn Olivia into a human for wasting their time. Now Olivia has to adjust to being human.