Zac is a teenage boy who decides to camp on Mako Island, unaware that three mermaids, Sirena, Nixie and Lyla, who are guardians of the island, are watching him. That night, when the full moon rises, the boy comes into contact with the magic water of the Moon Pool. The following morning, Zac wakes up discovering he has become a merman with a fish-like tail and the ability to control and manipulate water. His new-found merman abilities will cause problems for the mermaids.　　The three mermaids, curious about living on land, are transformed into humans while in the moon pool during a full moon, now having the ability to live like humans.。而两股恐怖力量冲击所笼罩的方圆百丈范围之内，纵横交错的出现了无数道黑色空间裂缝，似乎整个空间，在这一刻突然崩裂破碎。……