Siren has lived her life in an ordinary town, thinking she's an ordinary girl. On the eve of her twelfth birthday, however, she will learn that she is anything but. Like her mother, Siren is a mermaid... and now, she must begin the process that will allow her to transform and be at home in the water. But a group of hunters have also learnt the truth and are after Siren for her magical blood. With the help of her friends and the mermaid clan, Siren must avoid capture to complete her metamorphosis and fulfil her destiny.