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.。九公主不明所以，太子妃已将孩子抢到怀中用被子紧紧裹好，崩溃的大哭起来。房间里一时乱成一团。太子匆匆赶来，先将两个小丫头请出房间，又命太医仔细给孩子们检查身体，更将那盆栽挪到孩子们脑袋边，表情忽而慈祥怜……