The Little Mermaid

From the introduction: Welcome, Jumper, to a world that would appear to be much like your own, if it wasn’t for the merpeople beneath the waves. In the depths of the ocean, far out of humanity's reach, is the City of Atlantica. It is ruled over by King Triton who wields the illustrious Trident and commands the seven seas. His temper can turn a clear sky into a broiling storm, damning any ships in its path, and there’s nothing he hates more than humans. His youngest daughter, Ariel, doesn’t share his thoughts toward humankind in the slightest. In fact, she's very interested in the world above the waves, and this curiosity will set off a chain of events that will bring those worlds together. Unless you have a different future for this world in mind, Jumper.