ZacisateenageboywhodecidestocamponMakoIsland,unawarethatthreemermaids,Sirena,NixieandLyla,whoareguardiansoftheisland,arewatchinghim.Thatnight,whenthefullmoonrises,theboycomesintocontactwiththemagicwateroftheMoonPool.Thefollowingmorning,Zacwakesupdiscoveringhehasbecomeamermanwithafish-liketailandtheabilitytocontrolandmanipulatewater.Hisnew-foundmermanabilitieswillcauseproblemsforthemermaids.Thethreemermaids,curiousaboutlivingonland,aretransformedintohumanswhileinthemoonpoolduringafullmoon,nowhavingtheabilitytolivelikehumans.
Lilly,Ladapa,Thongkham,Belle,Jiratchaya,Kittavornsakul,Fay,Apisara,Lertwisettheerakul,Gene,Ornalin,Leelaburanathanakul,Benz,Atthanin,Thaninpanuvivat