YA supernatural action romance
Sixteen-year-old human girl meets a young merman and discovers an entire civilization under the sea with a war against spreading evil or "black water."
In Book One (BLACK WATER), we read about...
Spoiler
the sixteen-year-old underwater-breathing human discovering an entire civilization (Merlis) under the sea after encountering a noble merman. He noticed her seashell necklace and takes her with him. She learns that the mer people are endangered by a spreading evil called "black water" which is controlled by the sea witch and her court of sirens. Unable to be return to the land (because she gets attacked and the only way to heal her would be by mer medicine), the girl struggles to find her place in the mer court.