Emma and Rikki love swimming under water and exploring their new mermaid powers. Cleo however is not so sure, she'd do anything to give up her tail and become a normal girl again. But Cleo is alarmed when she hears a rumor of sea turtles becoming caught in fishermen's nets. Worst of all it's her fathers fishing boat that seems to be catching the turtles! Will Cleo learn to embrace her mermaid powers and use them to solve the mystery and clear her fathers name?