Transferred to a new school, teased, and tormented, 13-year-old Molly Finn learns that it may not be easy, but it's okay to be different. Molly's trouble begins when she finds out she is a mergirl and gets worse when she finds out why her parents have kept her heritage a secret. 
Mer Myths
The Birth of the Sea
When the first mer queen lost her beloved, killed by a fisherman's spear that pierced his heart, the mer queen cried so many tears that all the great, deep valleys of the land were covered with her sorrow. Before the death of her loved one, merpeople inhabited lakes and rivers; but when her lover died, the mer queen swore that her people would never return to the lakeshores or riverbanks, or to any place inhabited by land dwellers.
That is why the only stories we have of mer people come from sailors far out at sea.
Where the Sun Sleeps
Every season one of the Kings of the World held a grand celebration. The Kings of Middle Sea East and West invited the sun to be their honored guest. But the Kings of North and South Sea said the sun was too hot and would ruin their celebration. They refused the invite the Sky King to their waters. From then on, when the sun dropped into the water and rolled along the ocean floor each night, he refused to visit the North and South Seas, warming only the waters along the equator.
That is why the Arcticand Antarctic oceans froze and turned into desolate ice plains and glaciers.