Emma, Rikki and Cleo, three teenagers, found themselves marooned on an island after their boat runs out of fuel. The boat they took from a rich brat trying to pull a prank on Cleo. While on the island, they try to reach higher ground to get a cell phone signal, but Cleo falls down into a cavern. The two girls soon follow in a rescue attempt. They see a connecting pass through water as the only way out, but something magical happens as they all enter the water. Upon exiting on the other side, they get rescued by the harbor patrol. Next day, they find that upon touching the water they turn into mermaids. And not just that, but that they have the power to control the water itself.