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.。展辉和展颜发现大家对妈妈小心翼翼，妈妈不再送他们去学校，很奇怪。后来发现妈妈的肚子大起来了，才问吴雅：“奶奶，妈妈是不是有小宝宝了？”……