Emily Windsnap (abridged)

Emily Windsnap is thrilled to arrive at her new home, a secret island near the Bermuda Triangle where humans and merfolk live together, and where being a girl who grows a tail as soon as she enters the water isn't a problem. Being Emily, she can't resist exploring forbidden places, and as a result, she inadvertently wakes the kraken, the legendary deep sea monster who has been asleep for two hundred years.

The magic ring that Emily Windsnap - half mermaid, half ordinary girl - finds buried in the sand belongs to Neptune, and he wants it back. But the ring, once on, won't come off, and Neptune puts a terrible curse on Emily.