Its some sort of magical cave which is in the middle of the ocean, after been drifted there by the water, the three girls found them selves in the cave, Jackie found a spell and began to read it. After some seconds they were home at Emilys, and the next time they tuched water they turned into mermaids only 10 seconds after.
The tails they got were in the start; lime green but soon turned out into a darker coler. Its unknown how they will look in the commen seasons. The powers they got were making things dissappear, make things fly, and bring things to themselves - all of them got one of these powers each. The second powers were freezing things, control the water, and heat things and water up.
Mia had never had the lime green tail, and she only have one power still. Her power is to break things.
Its only known that five mermaids have been transformed in 'The Rock' - Faith, Jackie, Selena, Emily and Mia.