On leave in a shore side town, Johnny becomes interested in a young dark haired woman. They meet and he learns that she plays a mermaid in the local carnival. After strange occurrences, Johnny begins to believe that she may actually be a real mermaid that habitually kills during the cycle of the full moon.

Siren Phillips has lived her life thinking she's an ordinary girl, in an ordinary town. On the eve of her twelfth birthday, however, she learns that she is far from ordinary. Destined to turn into a mermaid at the age of twelve, Siren must struggle with her new reality, saying goodbye to her mother and friends while she transitions into the water. To make matters worse, a group of hunters is after her, trying to catch her.

In 1684 France, Louis XIV, the Sun King, is the most powerful and influential monarch on the planet. But his birthday is approaching along with a rare solar eclipse and he's worried about the future of France. His spiritual advisor, Pr̈e La Chaise, comforts him, while his physician, Dr. Labarthe informs him that scientists believe mermaids contain a life force that grants immortality. Louis XIV's quest for immortality leads him to capture a mermaid's...