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 normal again. But Cleo is alarmed when she hears a rumor of sea turtles becoming caught in fisherman's nets. Worst of all, it's her father's 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 father's name?