Three young mermaids, Serenity, Marine, and Pearl, who are tasked with protecting their magical island, Mako, from trespassers. When a land boy, Jacob, accidentally falls into the Moon Pool during a full moon, he is transformed into a merman, disrupting the mermaids' lives and forcing them to face consequences. The series explores Jacob's newfound abilities, the mermaids' struggle to reconcile their pod's rules with Jacob's existence, and the secrets of Mako Island.
